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  • Ultrastructure  (74)
  • Superconducting devices  (45)
  • Springer  (119)
  • 1980-1984  (119)
  • 1935-1939
  • 1925-1929
  • 1983  (119)
  • 1929
Collection
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  • Springer  (119)
Years
  • 1980-1984  (119)
  • 1935-1939
  • 1925-1929
Year
  • 1
    Electronic Resource
    Electronic Resource
    Instrumentation for biomagnetism (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 123-141 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si riesamina la strumentalizzazione adatta all’acquisizione di segnali biomagnetici. Si studiano separatamente i componenti di base del magnetometro, cioè gli SQUID, i trasformatori di flusso e i dewar. Si discutono i possibili miglioramenti alla strumentazione attuale e alle apparecchiature complete comprendenti scudi ferromagnetici o di correnti a vortice e si valuta la loro efficenza.
    Notes: Summary The instrumentation suitable for the acquisition of biomagnetic signals is reviewed. The basic magnetometer components,i.e. SQUIDs, flux transformers and dewars, are studied separately. Possible improvements to the present instrumentation as well as complete set-ups including ferromagnetic or eddy current shields are discussed and their efficiency evaluated.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455917
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  • 2
    Electronic Resource
    Electronic Resource
    First-gradient balancing of higher-order gradiometers (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 142-152 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si sviluppa un formalismo per la descrizione vettoriale e tensoriale di una procedura di bilanciamento e si sottolinea un metodo di bilanciamento di campo e di primo gradiente. Si discutono l’apparecchiatura sperimentale e le misurazioni del vettore di modo comune del primo gradienteC G 1.
    Notes: Summary A formalism for the vector and tensor description of a balancing procedure is developed and a first-gradient and field-balancing method is outlined. The experimental apparatus and measurements of the first-gradient common-mode vector,C G 1, are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455918
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  • 3
    Electronic Resource
    Electronic Resource
    Ultrastructural localization of adenylate cyclase and cAMP phosphodiesterase in the gastrulating chick embryo (1983)
    Springer
    Development genes and evolution 192 (1983), S. 42-44 
    Details
    ISSN: 1432-041X
    Keywords: Chick embryo ; Gastrulation ; Adenylate cyclase ; cAMP phosphodiesterase ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The ultrastructural localization of adenylate cyclase (E.C. 4.6.1.1.) and cAMP phosphodiesterase (PDE) (E.C. 3.1.4.17.) in the ectoderm of the developmental stage 4 chick embryo was studied. Adenylate cyclase was localized in the lateral surfaces of the ectodermal cells. In the primitive streak cells the enzymatic activity was observed on all the lateral surfaces, whereas in the periphery of the blastoderm the reaction product was localized in the apical parts of the lateral plasma membranes only. cAMP PDE localized in the apical cytoplasm of the ectodermal cells, with highest activity in the globular projections.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848768
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  • 4
    Electronic Resource
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    Electron microscopical study of self-differentiation potency in the chick embryonic endoderm cultured in vitro (1983)
    Springer
    Development genes and evolution 192 (1983), S. 171-178 
    Details
    ISSN: 1432-041X
    Keywords: Differentiation ; Digestive tract ; Endoderm ; Organ culture ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The self-differentiation potency of the endoderm of the chick embryo was investigated mainly by transmission electron microscopy. Endodermal fragments isolated from 4- to 6-day stomach or small intestine were cultured in the absence of mesenchyme and were able to differentiate in vitro into organ-specific epithelia. Endodermal fragments isolated from the stomach region differentiated into a pseudo-stratified epithelium with periodic acid Schiff-positive mucous granules in the apical cytoplasm, while those from the small intestinal region differentiated into a simple columnar epithelium with a striated border which was positive in alkaline phosphatase activity. These features are comparable with those of the mucous secretory epithelium of the normal embryonic stomach and the absorptive epithelium of normal embryonic small intestine, respectively. Next, the self-differentiation potencies were investigated of the upper and lower layers of the blastoderms, at stages 1–5 of Hamburger and Hamilton (H. and H.). Both stomach-type and small-intestine-type epithelia developed only when fragments of the lower layer isolated from the blastoderms older than stage 3 of H. and H. were cultured, suggesting that cells possessing the potency to differentiate into the stomach- and small-intestine-type epithelia exist in the definitive endoderm at the beginning of its formation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00848687
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  • 5
    Electronic Resource
    Electronic Resource
    Optimization of the second-order gradiometer base length that has been designed for the measurement of weak inhomogeneous magnetic fields (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 175-183 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si tratta il problema dell’ottimizzazione di sistemi di sensori gradiometrici metrici superconduttori di secondo ordine che sono stati progettati per la misurazione di campi magnetici deboli disomogenei in un ambiente disturbato magneticamente. Si considerano le condizioni di massimo rapporto segnale-rumore dell’uscita del quantomagnetometro superconduttote (SQM). Si analizza l’influenza dei parametri misurati della sorgente del segnale, del rumore di una sorgente di disturbo esterna e di quello proprio del magnetometro sulla selezione della lunghezza di base del gradiometro.
    Notes: Summary In this paper we deal with an optimization problem of the second-order superconducting gradiometric sensor systems that have been designed for measurement of the weak inhomogeneous magnetic fields in a magnetically disturbed environment. The conditions of maximum signalto-noise ratio of the output of superconducting quantum magnetometers (SQM) are considered. The influence of measured signal source parameters, of an outside disturbing source and of the own noise of the magnetometer on the gradiometer base length selection is analysed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455921
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  • 6
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    Optimizing vector magnetocardiographic lead fields by using a physical torso model (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 356-367 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono state esaminate l’idealità e la sensibilità di parecchi conduttori magnetocardiografici vettoriali usando un modello inomogeneo fisico del tronco. Si è trovato che la componente antero-posterioreX vettore magnetico del cuore è la piú facile da scoprire. Si suggeriscono conduttori ideali per le altre due componenti. Comunque questi hanno una sensibilità inferiore. Le differenze rispetto ai risultati di precedenti ricercatori sono state spiegate con le differenze tra i modelli.
    Notes: Summary The ideality and sensitivity of several vector magnetocardiographic leads were tested by using an inhomogeneous, physical torso model. The postero-anterior component of the heart’s magnetic vector was found easiest to detect. New, more ideal leads for the other two components are suggested. However, these have lower sensitivity. The differences from the results of former investigators can be explained by the differences of the models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455938
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  • 7
    Electronic Resource
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    Adaptive noise cancellation in neuromagnetic measurement systems (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 203-213 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è studiato lo spettro del rumore di un gradiometro superconduttore a derivata secon da in un agglomerato urbano. I dati sono stati ottenuti dal gradiometro con tre accelerometri ortogonali e un magnetometro a flussometro elettronico triassiale attaccato al dewar. Questi dati sono stati analizzati usando tecniche di elaborazione dei segnali, soprattutto un cancellatore adattativo di rumori, per ridurre i rumori nei dati del gradiometro. I risultati mostrano qui che il rumore dell’esterno e/o il rumore del movimento del dewar possono essere ridotti di 40 dB in potenza di rumore. Si è anche mostrato che, nel caso di basso rapporto segnale-rumore (S/N∼1), può essere estratta un’onda sunusoidale di 10 Hz. Questa tecnica non solo promette riduzione dei rumori, ma ha anche lo scopo d’identificare i segnali di rumore che potrebbero essere veramente considerati parte del responso evocato. L’analisi dei dati che contengono i responsi evocati è ora in corso.
    Notes: Summary The noise spectrum of a superconducting second-derivative gradiometer has been investigated in an urban environment. Data have been acquired from the gradiometer with three orthogonal accelerometers and a triaxial fluxgate magnetometer attached to the dewar. These data have been analyzed by using signal processing techniques, primarily an adaptive noise canceller, to reduce noise in the gradiometer data. Results shown here indicate that the environmental noise and/or the dewar motion noise can be reduced as much as 40 dB in noise power. It is also shown, in the case of poor signal-to-noise ratio (S/N∼1), that a 10 Hz sine wave can be extracted. This technique not only shows promise for noise reduction, but also aids in the identification of noise signals which might be misconstrued as part of the evoked response. Analysis of data containing evoked response is now underway.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455924
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  • 8
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    Magnetic sensors with good signal-to-interference discrimination (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 153-165 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si stabiliscono princípi per il progetto di sistemi di spire che generano campi magnetici distanti che diminuiscono secondo una potenza inversa alta della distanza. Secondo un principio di reciprocità queste disposizioni, quando usate come sensori in magnetometri ad induzione e SQUID, hanno una sensibilità intrinsecamento bassa per sorgenti distanti del campo magnetico.
    Notes: Summary Principles are established for the design of coil arrays which generate distant magnetic fields diminishing as a high inverse power of the distance. By a principle of reciprocity these arrays, when used as sensors in induction and SQUID magnetometers, have an inherently low sensitivity to distant sources of magnetic field.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455919
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  • 9
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    Measurement of biomagnetic fields using multichannel superconducting-magnetometer techniques (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 166-174 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è costruito un magnetometro SQUID differenziale a 3 canali per la misurazione simultanea delle 3 componenti ortogonali del campo magnetico nella stessa posizione. Si descrive la struttura dell’apparecchio e si mostrano i dati MCG misurati. Si discutono gli effetti d’interferenza tra i canali.
    Notes: Summary We have constructed a three-channel differential SQUID magnetometer for the simultaneous measurement of the three orthogonal components of the magnetic field in the same location. The structure of the device is described and MCG data measured are shown. Interference effects between the channels are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455920
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  • 10
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    Neuromagnetic measurements at hospital: Instrumentation and preliminary tests (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 184-194 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è costruito espressamente un sistema SQUID in un ospedale di Parigi, che permette indagini neuromagnetiche attinenti con applicazioni cliniche. Un gradiometro simmetrico di second’ordine lavora entro uno schermo per corrente parassite. Ciò è designato ad ottimizzare il costo e l’efficienza del sistema. Le sue prestazioni sono state sperimentate con dati da pazienti e da soggetti normali.
    Notes: Summary A SQUID system was specially built in a Parisian hospital, allowing neuromagnetic investigations dealing with clinical applications. A second-order symmetrical gradiometer works inside an eddy current shield. This was designed for optimizing the cost and the efficiency of the system. Its performances were tested with data from patients and normal subjects.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455922
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  • 11
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    A portable biomagnetic measuring system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 224-230 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si descrive la strumentazione per le applicazioni biomagnetiche. Le piccole dimensioni e la leggerezza del gradiometro SQUID permettono il facile trasporto e posizionamento dello strumento, rendendo cosí possibile le misurazioni biomagnetiche in una qualsiasi locazione in cui non ci siano rumori. L’apparecchio è provvisto di un alimentatore a batteria e, se riempito con 60 cm3 di elio liquido, funzionerà initerrottamente per 6 ore. L’apparecchio è adatto per la magnetocardiografia.
    Notes: Summary The instrumentation for biomagnetic applications is described. The small size and weight of the SQUID gradiometer permit easy transport and positioning of the instrument, thus making biomagnetic measurements possible in any noise-free location. The equipment is provided with a battery power supply, and, when filled with 60 cm3 of liquid helium, will operate continuously for 6 h. The device is suitable for magnetocardiography.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455926
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  • 12
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    Comparison between measured and simulated magnetocardiograms in a case of anterolateral myocardial infarction (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 301-310 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si confrontano i magnetocardiogrammi misurati in un caso di infarto miocardico anterolaterale con i corrispondenti magnetocardiogrammi simulati. I cambiamenti piú notevoli nell’MCG misurato si sono osservati nelle parti superiori e inferiori del torace come previsto dalla simulazione.
    Notes: Summary The MCGs measured in a case of an anterolateral myocardial infarction were compared with the corresponding simulated MCGs. The most distinctive changes in the measured MCGs were observed in the upper and lower parts of the thorax as predicted by the simulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455933
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  • 13
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    Determination of the spatial distribution of abnormal EEG and MEG from current dipole in inhomogeneous volume conductor (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 558-566 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La conduttività elettrica delle lesioni cerebrali varia con situazioni patologiche come l’edema e la calcificazione. È stato studiato mediante una simulazione con il computer l’effetto delle disomogeneità dei tessuti delle lesioni cerebrali sulle distribuzioni spaziali dei potenziali elettrici e dei campi magnetici sulla superficie del capo.
    Notes: Summary The electrical conductivity of brain lesions varies with pathological situations such as edema and calcification. The effect of the tissue inhomogeneities of brain lesions on spatial distributions of electrical potentials and magnetic fields over the surface of the head was studied by means of a computer simulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455954
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  • 14
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    Diagnostic assessment of human iron stores by measurement of hepatic magnetic susceptibility (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 567-581 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è sviluppato un metodo magnetico per misurazioni dirette non invasive del ferro di immagazzinamento epatico umano con uno suscettometro SQUID. Le determinazioni magneticain vivo e chimicain vitro del ferro epatico non eme sono strettamente correlate. Le misurazioni magnetiche dei depositi di ferro sono utili, dal punto di vista clinico, nella diagnosi dei disordini nel metabolismo del ferro.
    Notes: Summary A magnetic method for direct noninvasive measurements of human hepatic storage iron with a SQUID susceptometer has been developed.In vivo magnetic andin vitro chemical determinations of liver nonheme iron are closely correlated. Magnetic measurements of iron stores are clinically useful in the diagnosis of disorders of iron metabolism.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455955
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  • 15
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    The inverse problem in magnetopneumography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 594-607 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il problema inverso nella misurazione magnetical del polmone è stato studiato con un metodo che usa le ipotetiche distribuzioni del pulviscolo magnetico. Si sono fatte le minimizzazioni non vincolate e vincolate di una funzione obiettiva. Le simulazioni e l’analisi hanno mostrato l’efficacia del metodo.
    Notes: Summary The inverse problem in the magnetic measurement of the lung was studied with a method using hypothetical distributions of magnetic dust. Both unconstrained and constrained minimizations of an objective function were performed. Simulations and analysis showed the efficacy of the method.
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    URL: http://dx.doi.org/10.1007/BF02455957
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  • 16
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    Magnetopneumography in welders: Observations on relaxation and clearance (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 608-616 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è trovato che la velocità di decadimento del campo residuo ottenuto tramite magnetizzazione delle particelle ferromagnetiche trattenute nei polmoni dei saldatori è associato a fattori come la quantità di polvere trattenuta, il curriculum lavorativo e la consuetudine di fumare. Una velocità di decadimento piú rapida appare correlata con un piú rapido smaltimento delle particelle di fumo di saldatura nei fumatori.
    Notes: Summary It was found that the rate of decay of the remanent field obtained through magnetization of ferrimagnetic particles retained in the lungs of are welders is associated with factors such as amount of dust retained, occupational history and smoking habits. A faster decay rate was found to correlate with a faster clearance of welding fume particles in smokers
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    URL: http://dx.doi.org/10.1007/BF02455958
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  • 17
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    Magnetic particles in the lung: A probe for alveolar macrophage function (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 617-623 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Particelle ferromagnetiche immesse per via intratracheale nei polmoni sono fagocitate da macrofagi alveolari. Dopo che queste particelle sono state magnetizzate dal campo esterno, esse producono un campo residuo che decade rapidamente a causa del disallineamento delle particelle dovuto al movimento citoplasmatico (rilassamento). I cambiamenti nel valore di rilassamento nel tempo successivo all’immissione potrebbero essere connessi alla mobilità citoplasmatica.
    Notes: Summary Ferrimagnetic particles instilled intratracheally into the lungs are phagocytized by alveolar macrophages. After these particles are magnetized by an external field, they produce a remanent field which decays rapidly due to particle misalignment from cytoplasmic motion (relaxation). Changes in relaxation rate with time following instillation might be related to cytoplasmic motility.
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    URL: http://dx.doi.org/10.1007/BF02455959
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  • 18
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    Magnetic-susceptibility plethysmography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 624-641 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La pletismografia a suscettività magnetica (MSPG) è un nuovo metodo proposto per controllare i cambiamenti del volume cardiaco. Si riesaminano il principio di misurazione e i lavori recenti di altri ricercatori. Si studia l’effetto del movimento legato al cuore della cassa toracica anteriore sul segnale MSPG.I risultati suggeriscono che il movimento del confine cassa toracica-aria può contribuire in modo significativo (∼75%) al segnale MSPG quando è registrato vicino al cuore.
    Notes: Summary Magnetic-susceptibility plethysmography (MSPG) is a new method proposed for monitoring cardiac-volume changes. The measurement principle and recent work by other investigators are reviewed. The effect of the cardiac-related motion of the anterior chest wall on the MSPG signal is studied. The results suggest that the motion of the chest-wall-air boundary may contribute significantly (∼75%) to the MSPG signal when recorded near the heart.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455960
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  • 19
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    Magnetic signals from human skeletal muscles (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 642-649 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stata esaminata la forma d’onda d’impulso per il magnetomiogramma (MMG) dell’arto inferiore destro umano. Le durate tipiche degl’impulsi sono di circa (10÷20) ms. La variazione spaziale del MMG suggerisce un’origine nei muscoli anteriori della tibia.
    Notes: Summary The pulse wave form for the magnetomyogram (MMG) of the human right leg was examined. The typical pulse durations are about (10÷20) ms. The spatial variation of the MMG suggests a source in the anterior muscles.
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    URL: http://dx.doi.org/10.1007/BF02455961
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  • 20
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    d.c. Magnetic fields of the human leg as a function of position and relaxation (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 650-659 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Le ricerche sul campo magnetico intorno alla gamba umana con l’uso di un magnetometro SQUID producono risultati consistenti e riproducibili che possono essere rappresentati mediamente due linee di corrente, orientate inversamente, parallele all’asse della gamba. I campi sono condizionati dall’attività muscolare, che decade col tempo di rilassamento della gamba.
    Notes: Summary Investigations of the magnetic field around the human leg using a SQUID magnetometer yield consistent, reproducible results which can be modelled by 2 oppositely oriented line currents parallel to the leg axis. The fields are affected by muscle activity, decaying with the time of relaxation of the leg.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF02455962
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    An eddy-current-shielded room with a partially closed entrance (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 195-202 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si mostra che miglioramenti sostanziali possono essere ottenuti nelle proprietà di schermatura di una stanza schermata da corrente parassite coprendo l’accesso con lamine conduttrici. I risultati suggeriscono che non è necessario installare una porta conduttrice e mostrano che è il caso di coprire una piccola parte della porta in modo permanente.
    Notes: Summary We show that substantial improvements can be obtained in the shielding properties of an eddy-current-shielded room by covering the doorway with conductive plates. Results suggest that it is unnecessary to install a conductive door and show that it is worthwhile covering a small part of the doorway permanently.
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    URL: http://dx.doi.org/10.1007/BF02455923
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    High-resolution recordings of thePR segment in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 248-254 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il magnetocardiogramma ad alta risoluzione è stato registrato mediante magnetometri superconduttori in 12 volontari sani utilizzando la camera schermata di Berlino per ridurre il livello di rumore elettromagnetico. La morfologia del trattoPR magnetico è caratterizzata dalle «rampe» in precedenza osservate, sulle quali s’inseriscono segnali. A volte la forma d’onda appare complessa.
    Notes: Summary ThePR interval of magnetocardiograms has been measured with a SQUID sensor in the Berlin magnetically shielded room. In addition to previously reported ramps with isolated superimposed signals in several cases a structured morphology has been found.
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    URL: http://dx.doi.org/10.1007/BF02455928
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    Atrial activity during thePR segment of the MCG (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 266-279 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati osservati segnali degradanti nel segmentoPR dei magnetocardiogrammi normali registrati da 5 cani. Sono state osservate rampe maggiori dopo aver indotto con farmaci il blocco del nodo atrioventricolare di primo grado, ed è stata osservata una completa ripolarizzazione atriale a seguito d’isolate contrazioni atriali in due animali con blocco di secondo grado. Queste rampe, che variano fino a 6.7 pT in ampiezza e provengono dagli atri, possono complicare l’individuazione magnetica dell’attività di His-Purkinje.
    Notes: Summary Sloping signals were observed in thePR segment of normal magnetocardiograms recorded from five dogs. Larger ramps were observed after first-degree AV nodal blockade was induced pharmacologically, and complete atrial repolarization was observed following isolated atrial contractions in two animals with second-degree block. These ramps, ranging up to 6.7 pT in size and arising from the atria, may complicate magnetic detection of His-Purkinje activity.
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    URL: http://dx.doi.org/10.1007/BF02455930
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    High-resolution magnetic measurements of human cardiac electrophysiological events (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 231-247 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto La motivazione fondamentale per lo studio dei fenomeni elettrofisiologici cardiaci tramite il metodo biomagnetico è dovuta al fatto che questa tecnica offre un’alta risoluzione spaziale e sembra fornire informazioni complementari rispetto alle sole registrazioni elettriche. Fino ad oggi l’interesse degli studiosi si è concentrato su due differenti fenomeni cardiaci: 1) lo studio dell’attività del sistema di conduzione atrioventricolare e 2) lo studio della depolarizzazione ventricolare anormalmente ritardata (late potentials). L’interesse clinico per lo studio non invasivo del sistema di His-Purkinje (HPS) è ben noto. Registrazioni cliniche non invasive di late potentials sono particolarmente desiderabili in quanto possono essere preziosi indicatori di rischio di morte improvvisa. In questo lavoro si presenta una rassegna sullo stato delle ricerche in entrambi i campi d’indagine.
    Notes: Summary The fundamental motivation for investigating cardiac electrophysiological phenomena by means of the biomagnetic method has been that this technique should have added spatial resolution and provided complementary information as opposed to electric recordings only. So far the interest of experimentalists has been concentrated on two different kinds of cardiac phenomena: 1) the study of the activity of the cardiac conduction system and 2) of abnormally delayed ventricular depolarization (late potentials). The clinical interest for the noninvasive investigation of the His-Purkinje system (HPS) is well known. Noninvasive clinical recording of late potentials is particularly desirable as they seem to be precious markers for risk of sudden death. A review of the state of research in both fields is presented in this paper.
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    URL: http://dx.doi.org/10.1007/BF02455927
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    Magnetic measurements and modelling for the investigation of the human-heart conduction system (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 280-290 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Ein dal 1980 è iniziato uno studio sistematico dell’attività del sistema di His-Purkjnje (HPS) su soggetti normali e patologici con il metodo biomagnetico. Allo scopo di risolvere il problema di quanta parte dei segnali misurati sia attribuibile al sistema di His-Purkinje e quanta piuttosto alla ripolarizzazione atriale, è stata recentemente sviluppata una strumentazione appositamente disegnata per misure sul HPS e con una sensibilità di $$20fT/\sqrt {Hz}$$ nella banda di frequenze interessanti ((0.5÷300) Hz). Al contempo si è altresí sviluppato un nuovo modello teorico in stretta corrispondenza con le caratteristiche anatomiche del HPS che fornisce una distribuzione di campo magnetico sul torace in buon accordo qualitativo con i risultati sperimentali.
    Notes: Summary Since 1980, systematic investigations of the activity of the His-Purkinje system (HPS) by the biomagnetic method have been reported on both normal subjects and patients affected by different kinds of conduction disturbances. A first attempt to interpret the experimental results by means of a theoretical model satisfactorily accounted for the measured «ramp» patterns. Moreover, a good temporal coincidence was observed between magnetic signals and invasively recorded His bundle electrograms (HBE). An alternative explanation of the «ramp» pattern, in terms of atrial repolarization, has been recently proposed on the basis of animal experimental investigation. In order to try to solve this problem, we have carried out a twofold approach: a new second-order gradiometer, specifically designed for HPS activity investigation has been successfully set up and tested; it provides a sensitivity of $$20fT/\sqrt {Hz}$$ in the band width of interest ((0.5÷300) Hz). Second, a new model based on a closer correspondence to anatomical features of the HPS has been developed. This model provides well-defined patterns which are in quite good agreement with experimental results.
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    URL: http://dx.doi.org/10.1007/BF02455931
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    The mapping of the measured cardiac electric potential and magnetic-field distribution (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 311-323 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si registra la distribuzione sia del potenziale elettrico cardiaco sulla superficie del corpo che del campo magnetico cardiaco vicino al torace e alla schiena in momenti fissi del ciclo cardiaco. Le caratteristiche generali di entrambi i tipi di mappa sono semplici e riproducibili, inoltre ciascuno di essi fornisce informazioni differenti.
    Notes: Summary The distribution of both the cardiac electric potential on the body surface and the cardiac magnetic field near the chest and back is recorded at fixed time instants of the heart cycle. The general features of both types of maps are simple and reproducible, moreover they both reveal different information.
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    URL: http://dx.doi.org/10.1007/BF02455934
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    The influence of inhomogeneities on the cardiac-magnetic-field distribution (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 324-339 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati eseguiti calcoli numerici sul campo magnetico generato dal cuore durante la depolarizzazione ventricolare. Lo scopo di questo lavoro è studiare il contributo d’inomogeneità nel conduttore di volume al campo totale e stabilire l’influenza dei gradiometri usati nelle registrazioni sperimentali.
    Notes: Summary Numerical computations were performed on the magnetic field generated by the heart during ventricular depolarization. The purpose of this study was to investigate the contribution of inhomogeneities in the volume conductor to the total field and to establish the influence of gradiometers as used in experimental recordings.
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    URL: http://dx.doi.org/10.1007/BF02455935
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    High-resolution magnetocardiographic recordings of theST segment in patients with electrical late potentials (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 340-345 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il magnetocardiogramma ad alta risoluzione, registrato in 22 pazienti affetti da pregresso infarto del miocardio, ha permesso di rilevare in 3 casi la presenza di segnali di ampiezza tra 0.4 e 3 pT temporalmente correlati a depolarizzazioni tardive elettriche. Si discutono de differenze tra segnali magnetici ed elettrici e il loro possibile significato fisiopatologico.
    Notes: Summary High-resolution magnetocardiograms of patients with recent myocardial infarction have been recorded. In three cases, signals have been found in theST segment that are time correlated with simultaneously recorded late electric potentials.
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    URL: http://dx.doi.org/10.1007/BF02455936
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    On the influence of the volume conductor in magnetocardiography: an experimental approach (1983)
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    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 346-355 
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    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Per studiare l’effetto della geometria del conduttore di volume, sono stati compiuti esperimenti usando cuori di coniglio isolati. È stato osservato un aumento del segnale magnetico con l’aumentare della dimensione del conduttore di volume. Si discutono i risultati usando un dipolo di corrente a origine fissa e un modello di sorgente di tensione per il cuore.
    Notes: Summary To study the effect of the volume conductor geometry on the MCG, experiments using isolated rabbit hearts were done. An increase of the magnetic signal when increasing the volume conductor’s size was observed. The results are discussed by using a fixed-origin current dipole and a voltage source model for the heart.
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    First magnetic measurements of action currents in isolated cardiac Purkinje fibers (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 368-378 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano le prime misurazioni del campo magnetico associato col potenziale d’azione in un fascio di fibre cardiache di Purkinje isolate. Le nostre scoperte dimonstrano la fattibilità dell’uso di tecniche magnetiche per misurare le correnti assiali in un gruppo di cellule cardiache ad attività spontanea.
    Notes: Summary We present the first measurements of the magnetic field associated with the action potential in a bundle of isolated cardiac Purkinje fibers. Our findings demonstrate the feasibility of using magnetic techniques to measure the axial current in a bundle of spontaneously active cardiac cells.
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    URL: http://dx.doi.org/10.1007/BF02455939
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    Inferences concerning anatomy and physiology of the human brain based on its magnetic field (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 379-409 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetic (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si riesaminano le ricerche sul campo magnetico indotto compiute negli ultimi due anni. Questi studi hanno mostrato che la tecnica magnetica si puó usare 1) per rivelare aspetti complementari delle fonti di corrente comuni al potenziale indotto, 2) per identificare l’organizzazione della corteccia cerebrale e delle arce subcorticali e 3) per misurare le proprietà funzionali delle aree neurali attive le cui posizioni sono identificate.
    Notes: Summary Research in the evoked magnetic field reported in the last two years is reviewed. The studies have shown that the magnetic technique may be used 1) to reveal complementary aspects of the current sources common to evoked potential, 2) to identify the organization of the cerebral cortex and subcortical areas of the brain and 3) to measure functional properties of the active neural areas whose locations are identified.
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    URL: http://dx.doi.org/10.1007/BF02455940
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    Retinotopic map on the visual cortex for eccentrically placed patterns: First noninvasive measurement (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 410-419 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Il campo magnetico corticale osservato, suscitato da uno stimolo presentato a varie eccentricità nel campo visivo, è stato interpretato come derivante da dipoli di corrente lungo la scissura longitudinale. La profondità della sorgente aumenta con l’aumento dell’eccentricità, in accordo con la classica mappatura retinotopica.
    Notes: Summary The observed cortical magnetic field evoked by a stimulus presented at various eccentricities in the visual field was interpreted as arising from current dipoles along the longitudinal fissure. The depth of the source increased as the eccentricity was increased, in agreement with the classical retinotopic map.
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    URL: http://dx.doi.org/10.1007/BF02455941
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    Neuromagnetic localization of two components of the transient visual evoked response to patterned stimulation (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 420-428 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si esamiano i componenti elettrici e magnetici della risposta stimolata visiva del cervello, con picchi a 120 e 180 ms dopo lo stimolo. I risultati mostrano che entrambi i componenti magnetici sono localizzati nella corteccia occipitale superficiale tangenziale al cuoio capelluto. La distribuzione diM120 suggerisce che i generatori dei componenti elettrici e magnetici sono correlati, ma il campo magnetico elettrico registrato è una modificazione elaborata di quello prodotto dalla sorgente.
    Notes: Summary Corresponding electrical and magnetic components of the brain’s visual evoked response peaking at 120 and 180 ms poststimulus are examined. Results show that both magnetic components are localized in the superficial occipital cortex tangential to the scalp. The distribution ofM120 suggests that the generators for the electrical and magnetic components are related, but the electrical field recorded is an elaborate modification of that produced by the source.
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    Somatosensory evoked magnetic fields: Mappings and the influence of the stimulus repetition rate (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 429-437 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Campi magnetici indotti dalla sensibilità somatica sono stati confrontati con i corrispondenti potenziali elettrici sul cuoio capelluto allo scopo di studiare le loro sorgenti neurali. Le mappature delle risposte magnetiche hanno mostrato attività a livello delle cortecce di sensibilità somatica primarie e secondarie. Ulteriori sorgenti oltre a queste aree sembrano essere coinvolte nella generazione dei potenziali del cuoio capelluto a vertice somatosensoriali.
    Notes: Summary Somatosensory evoked magnetic fields were compared with corresponding electric scalp potentials in order to study their neural sources. Mappings of the magnetic responses showed activity at the primary and secondary somatosensory cortices. Additional sources besides these areas seem to be involved in the generation of the somatosensory vertex scalp potentials.
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    Some tentative model considerations based on experimental neuromagnetic data (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 438-459 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto In questo lavoro si presentano alcuni tentativi di considerazioni modello, basati sul concetto di dipolo di corrente equivalente per tener conto delle risposte sonore stimolate osservate, con lo scopo di tentare un confronto delle variazioni in ampiezza e latenza con calcoli basati sul modello di nervo altamente semplificato di Rall. Si presenta un’analisi fenomenologica dei dati sperimentali sul campo magnetico sonoro tardo evocato dalla corteccia uditiva umana. Qui si pone l’accento sulle relazioni tra le proprietà del segnale (per esempio, ampiezza e latenza) e tra le proprietà del segnale e le proprietà dello stimolo (per esempio, ampiezza/latenza e frequenza in discesa relativa Δf/f per uno stimolo con frequenza in discesa) piuttosto che su problemi correlati con la posizione del dipolo di corrente equivalente, per esempio l’organizzazione tonotopica discussa da Elberlinget al. e Romaniet al. Si presentano alcuni risultati di un calcolo numerico basato su un modello a cavo lineare e li si confronta con i risultati sperimentali.
    Notes: Summary In this paper we present some tentative model considerations, based on the concept of an equivalent current dipole to account for observed auditory evoked responses, with the aim of attempting a comparison of variations in amplitude and latency with calculations based on Rall’s greatly simplified nerve model. A phenomenological analysis of experimental data on the late, auditory evoked magnetic field from the human auditory cortex is presented. The emphasis is here placed on relations between signal properties (e.g. amplitude and latency) and between signal properties and stimulus properties (e.g. amplitude/latency and relative frequency glide Δf/f for a frequency glide stimulus) rather than on questions related to the location of the equivalent current dipole,e.g. the tonotopic organization discussed by Elberlinget al. and by Romaniet al.. Some results of a numerical calculation based on a linear-cable model are presented and compared with experimental results.
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    Studies of auditory evoked magnetic and electric responses: Modality specificity and modelling (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 471-483 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Le sorgenti di risposte uditive magnetiche ed electtriche stimolate sono state formate con dipoli a corrente multipli. L’attività a livello delle cortecce uditive, 2.6 cm al di sotto della calotta cranica, spiega la distribuzione di campo osservata $$\overline {N100m}$$ . Un’ulteriore sorgente di corrente vicino al vertice è necessaria per spiegare le corrispondenti distribuzioni di potenziale. La posizione delle sorgenti di corrente di $$\overline {N100m}$$ non ha mostrato alcuna dipendenza sistematica dalla frequenza tonale.
    Notes: Summary The sources of auditory evoked electric and magnetic responses were modelled with multiple current dipoles. The activity at the auditory cortices, 2.6 cm beneath the skull, explains the observed $$\overline {N100m}$$ field distribution. An additional current source near the vertex is needed to explain the corresponding potential distributions. The locations of the current sources of $$\overline {N100m}$$ did not show any systematic dependence on the tonal frequency.
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    URL: http://dx.doi.org/10.1007/BF02455946
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    Auditory evoked magnetic fields: a replication, with comments on the magneticP50 analog (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 460-470 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati registrati campi magnetici uditivi indotti (AEF) e potenziali uditivi indotti EEG (AEP) dalle regioni corticali uditive destra e sinistra di 12 soggetti normali adulti. Il sensore magnetico era un gradiometro SQUID a forma di otto con una linea di base di 4 cm orientato in modo da essere massimamente sensibile a un dipolo di corrente orientato perpendicolarmente alla fissure di Sylvio. Gli stimoli erano impulsi sonori di 1 kHz, lunghi 100 ms con un intervallo modale tra stimoli di 700 ms emessi a livelli di pressione sonora di 40, 60, 80 e 100 dB. Si è trovato che l’ampiezza AEF è correlata all’intensità dello stimolo in modo quadratico, l’ampiezza AEP in modo, lineare. Gli AEF erano di ampiezza maggiore in risposta alla stimolazione contralaterale che in risposta alla stimolazione ipsilaterale. Gli AEP non presentano questa relazione. In un secondo esperimento gli AEF e AEP dell’emisfero destro in risposta al tono di stimolazione nell’orecchio controlaterale in questi 12 soggetti sono stati combinati con dati simili precedenti su 24 soggetti, ottenendo cosí un totale di 36 soggetti, per esaminare la comparabilità della forma dell’onadaP50 di AEP e dell’analogaP50 di AEF. Si è trovato che la latenza dellaP50 decrese in funzione dell’intensità crescente dello stimolo sia per AEF che per AEP, e che la latenza diP50 è decisamente inferiore nelle registrazioni magnetiche rispetto alle registrazioni del potenziale.
    Notes: Summary Auditory evoked magnetic fields (AEFs) and EEG auditory evoked potentials (AEPs) were recorded from left and right auditory cortical regions of 12 normal adult subjects. The magnetic sensor was a figure-eight SQUID gradiometer with a 4 cm baseline oriented so as to be maximally sensitive to a current dipole oriented normal to the Sylvian fissure. Stimuli were 100 ms long 1 kHz tone pips with a modal interstimulus interval of 700 ms delivered at sound pressure levels of 40, 60, 80 and 100 dB. AEF amplitude was found to be related to stimulus intensity in a quadratic fashion, AEP amplitude in a linear fashion. AEFs were of larger amplitude in response to contralateral as compared to ipsilateral stimulation. AEPs did not exhibit such a relationship. In a second experiment right-hemisphere AEFs and AEPs in response to contralateral ear tone stimulation in these 12 subjects were combined with similar previous data from 24 subjects, providing a total of 36 subjects, to examine the comparability of the AEPP50 wave form and the AEFP50 analog. The latency of theP50 was found to decrease as a function of increasing stimulus intensity for both AEFs and AEPs, and theP50 latency was consistently shorter in magnetic compared to potential recordings.
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    Cerebral magnetic fields associated with voluntary limb movements in man (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 484-494 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto I movimenti volontari degli arti sono preceduti da spostamenti MEG che cominciano già 1.2s prima del movimento. Questi spostamenti invertono la polarità sull’area di rappresentazione della corteccia motoria dell’arto in questione.
    Notes: Summary Voluntary limb movements are preceded by MEG shifts beginning even as early as 1.2 s before the movement. These shifts reverse polarity above the cortical motor representation area of the limb concerned.
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    URL: http://dx.doi.org/10.1007/BF02455947
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    Slow magnetic fields of the brain preceding movement and speech (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 495-504 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Sono stati registrati i campi magnetici del cervello che precedono i movimenti autonomi delle dita della mano, del piede e della dita del piede stesso, i movimenti delle dita della mano e del piede causati da uno stimolo e la parola. Sono stati trovati lenti spostamenti dei campi magnetici con morfologia simile ai coincidenti potenziali elettrici, ma con distribuzioni molto diverse. Si discutono le deduzioni ottenute dai dati sulla localizzazione dei generatori cerebrali.
    Notes: Summary Magnetic fields of the brain were recorded preceding selfinitiated finger, foot, toe movements, stimulus-triggered finger and toe movements, and speech. Slow magnetic-field shifts were found with morphology similar to coincident electrical potentials, but with very different distributions. Inferences from the data about localization of cerebral generators were discussed.
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    URL: http://dx.doi.org/10.1007/BF02455948
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    Magnetic fields associated with the brain’s response to infrequent events (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 505-511 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si è studiato il campo magnetico prodotto dal cervello prendendo in considerazione una varietà di eventi rari. Si riporta il carattere temporale della risposta a un raro stimolo uditivo. Il campo magnetico appare offrire un’utile nuova sonda dell’attività endogena nel cervello umano.
    Notes: Summary We have studied the magnetic field produced by the brain when attending to a variety of rare events. The temporal character of the response to a rare auditory stimulus is reported. The magnetic field appears to offer a useful new probe of endogeneous activity in the human brain.
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    URL: http://dx.doi.org/10.1007/BF02455949
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    Magnetic study of the spontaneous brain activity of normal subjects (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 538-546 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Uno studio sull’attività spontanea del cervello in soggetti normali è stato eseguito con il metodo neuromagnetico. Sono stati usate 2 diverse strumentazioni per le misure magnetiche. Ambedue usavano gradiometri di second’ordine disegnati specificatamente per gli studi sul cervello: 2.9 cm di diametro, 5 cm di baseline. Uno SQUID r.f. e uno SQUID d.c. erano accoppiati ai gradiometri. I livelli di rumore misurati sono stati rispettivamente di $$40fT/\sqrt {Hz}$$ e $$25fT/\sqrt {Hz}$$ . In alcuni soggetti sono state effettuate mappe di campi magnetici generati dall’attività spontanea del cervello. Le mappe dell’ampiezza media dei segnali del ritmo α hanno mostrato 2 massimi dell’attività su 2 regioni simmetriche dello scalpo. Comunque, malgrado una generale simmetria fra gli emisferi, la complessità delle mappe misurate suggerisce una corrispondente complessità dei generatori responsabili dell’attività α.
    Notes: Summary An investigation of the spontaneous brain activity from normal subjects has been carried out by means of the neuromagnetic method. Two different systems were used for magnetic measurements. Both used 2nd-order gradiometers specifically designed for brain studies: 2.9 cm diameter, 5 cm baseline. A r.f. SQUID and a d.c. SQUID were coupled to the gradiometers. The measured noise levels are $$40fT/\sqrt {Hz}$$ and $$25fT/\sqrt {Hz}$$ , respectively. Thorough magnetic mapping of the spontaneous activity was performed on a few subjects. By mapping the average amplitude of the α-rhythm signals two maxima of activity over two symmetric regions of the scalp were clearly observed. Despite a general symmetry between hemispheres, however, the complexity of the measured maps suggests a corresponding complexity of the generators responsible for α-activity.
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    Alternatives to the SQUID magnetometer for some biomagnetic measurements (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 214-223 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; PACS. 85.25 ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si discutono magnetometri del tipo del flussometro elettronico e di risonanza (precisione libera, pompata otticamente) che possono in qualche caso sostituire il magnetometro SQUID. Si descrivono i princípi di funzionamento, la sensibilità, l’intervallo dinamico e la risposta di frequenza. Si dà un accenno riguardo l’applicazione di questi magnetometri nelle misurazioni biomagnetiche.
    Notes: Summary Flux gate and resonance type of magnetometers (free precession, optically pumped), which can in some cases replace the SQUID magnetometer, are discussed. The principles of operation, sensitivity, dynamical range and frequency response are described. The application of these magnetometers for biomagnetic measurements is mentioned.
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    URL: http://dx.doi.org/10.1007/BF02455925
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    The magnetic field produced by the conduction system of the human heart (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 255-265 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto È stata sfruttata la risoluzione spaziale del sensore magnetico per fornire stime numeriche del contributo atriale ai campi magnetici registrati esattamente prima della depolarizzazione ventricolare. Si trova che il contributo è piccolo, e questo rafforza l’interpretazione originale secondo la quale questi campi derivano principalmente dal sistema di conduzione del cuore.
    Notes: Summary We have exploited the spatial resolution of the magnetic sensor to provide numerical estimates of the atrial contribution to magnetic fields recorded just prior to ventricular depolarization. The contribution is found to be small, strenghening our original interpretation that such fields originate mostly in the conduction system of the heart.
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    URL: http://dx.doi.org/10.1007/BF02455929
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    High-resolution isofield mapping in magnetocardiography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 291-300 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano i risultati preliminari ottenuti costruendo mediante computer mappe di distribuzione di campo magnetico sulla base di registrazioni ad alta risoluzione effettuate con magnetometro superconduttore. La procedura è stata applicata per esaminare i MCG di 16 pazienti affetti da pregresso infarto del miocardio. Sulla base di questa elaborazione è stato possibile dividere i pazienti in due classi, una delle quali contiene tutti i pazienti con depolarizzazioni tardive.
    Notes: Summary A possible clinical application of a high-resolution magnetic isofield contour mapping technique in cardiography is discussed. Preliminary results are presented in applying this technique to patients with recent myocardial infarction. The patients could be divided into two classes; one of them contains patients with electrical late potentials as a subclass.
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    Magnetic measurements of action currents in an isolated lobster axon (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 512-516 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Si presentano le prime misurazioni del campo magnetico prodotto da correnti di azione che si propagano lungo l’assone singolo di un nervo gigante. Questi dati sono stati ottenuti con un trasduttore a bobina toroidale e un amplificatore o semiconduttore a temperatura ambiente.
    Notes: Summary We present the first measurements of the magnetic field produced by action currents propagating along a single giant nerve axon. These data were obtained with a toroidal pick-up coil and a room temperature semiconductor amplifier.
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    URL: http://dx.doi.org/10.1007/BF02455950
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    Clinical magnetoencephalography (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 517-537 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Finora la magnetoencefalografia spontanea (MEG) in soggetti normali e patologici non è stata investigata a fondo. Si conoscono pochissimi contributi in questo campo. A parte il lavoro del gruppo di biomagnetismo di Roma, il solo contributo clinico finora è stato quello di Hughes e collaboratori che era abbastanza limitato nel numero e nella scelta dei soggetti studiati. La nostra esperienza condotta fin dal 1980 su un gran numero di casi (principalmente epilessie focali) mostra che il MEG può evidenziare attività significative anche se non sono presenti anormalità EEG; esso ha inoltre una risoluzione spaziale maggiore rispetto all’EEG. I foci epilettici mostrano un’area limitata di attività massima. Finora non è stata osservata nessuna evidenza sperimentale di una differente distribuzione delle ampiezze del campo sullo scalpo. La risoluzione spaziale del MEG riguarda anche la possibilità di risolvere la morfologia dei segnali EEG (per esempio onde aguzze EEG risolte in gruppi di spikes dal MEG) o di separare topograficamente le anormalità EEG mescolate e non ben localizzate (per esempio, attività delta ed epilettiche mescolate nell’EEG e discriminate nel MEG). I migliori risultati si osservano quando la localizzazione è nella corteccia esterna. Dopo una descrizione del materiale studiato, si sottolinea l’importanza dei risultati ottenuti per la prima volta in casi di epilessie focali.
    Notes: Summary So far spontaneous magnetoencephalography (MEG) in normal and pathological subjects has not been deeply investigated. Very few contributions in this field are available. Aside from the work of the Rome biomagnetic group in this field, the only clinical contribution up to now has been that of Hughes and co-workers which was rather limited in the number and in the selection of subjects investigated. Our experience, carried out since 1980 on a large number of cases—mainly focal epilepsies— shows that the MEG may evidence significant activities even if EEG abnormalities are not present and has a higher spatial resolution with respect to the EEG. Epileptic foci show a limited area of maximal activity. So far no experimental evidence of a different distribution of field amplitude over the scalp has been observed. The spatial resolution of the MEG also regards the possibility of resolving the morphology of EEG signals (for instance, EEG sharp waves resolved into groups of spikes by MEG) or topographically separate EEG abnormalities mixed up and not well localized (for instance, delta and epileptic activities mixed up in the EEG, but differently in the MEG). The best results are observed when the localization is in the outer cortex. After a description of the material studied, the importance of the results obtained for the first time in cases of focal epilepsies is outlined.
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    Localization of epileptic foci by means of biomagnetic measurements (1983)
    Springer
    Il nuovo cimento della Società Italiana di Fisica 2 (1983), S. 547-557 
    Details
    ISSN: 0392-6737
    Keywords: Biomagnetism (including magnetocardiography) ; Superconducting devices ; superconducting magnets
    Source: Springer Online Journal Archives 1860-2000
    Topics: Physics
    Description / Table of Contents: Riassunto Durante l’ultimo anno gli autori hanno condotto una ricerca sistematica su un gran numero di soggetti patologici registrando simultaneamente l’EEG e il MEG. La presente versione del nostro apparato sperimentale permette di effettuare misure MEG con un solo sensore magnetico, impedendo la rilevazione simultanea di attività MEG su punti differenti della testa. Ciò ha condotto gli autori a concentrarsi sulle epilessie focali. Fin dalle prime misure il sensore magnetico ha dimostrato un notevole potere localizzante, rafforzando l’interesse per la localizzazione in casi patologici. In questo lavoro si riportano risultati che sembrano confermare la straordìnaria capacità delle misure MEG nel localizzare sorgenti di attività cerebrali patologiche in casi di epilessie focali.
    Notes: Summary During the last year the authors have been carrying out a systematic investigation on a large number of pathological subjects simultaneously recording the EEG and the MEG. The present version of our experimental apparatus allows MEG measurements with only one magnetic detector, thus preventing the detection of simultaneous MEG activities over different points of the head. This has led the authors to concentrate upon focal epilepsies. Since the first measurements a remarkable localizing power was shown by the magnetic detector, thus strengthening the interest in pathological localization. In this contribution we report results which seem to confirm the extraordinary capability of MEG measurements to localize sources of pathological brain activities in cases of focal epilepsies.
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    Ultrastructure of tuberculate spores in Streptomyces thermoviolaceus (1983)
    Springer
    Archives of microbiology 134 (1983), S. 295-298 
    Details
    ISSN: 1432-072X
    Keywords: Actinomycetes ; Streptomyces thermoviolaceus ; Sporogenesis ; Spore ornamentation ; Cupular knobs ; Sheath ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The sporogenesis of aerial spores in Streptomyces thermoviolaceus corresponded to a common sporulation type in the genus. The sporulation septum was composed of an outer ring-shaped constriction wall and an inner interspace septum arising by the inwards growth of a double annulus. In mature spores the wall was composed of two layers, the outer one was part of the parent hyphal wall and septum material, the inner one was formed de novo. The spore chains were enclosed by the thin breakable sheath containing small rod-like elements. The ornamentation in the form of knobs, which were a characteristic feature of the species originated from the sheath. The knobs were hemispherical particles with an inner electron dense core and an outer electron transparent shell. The term “cupular knobs” was suggested for this type of tuberculate ornamentation. Frequently, the knobs became detached from the surface in which case the inner core separated easily from the shell.
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    Chroococcus S24 and Chroococcus N41 (cyanobacteria): morphological, biochemical and genetic characterization and effects of water stress on ultrastructure (1983)
    Springer
    Archives of microbiology 135 (1983), S. 81-90 
    Details
    ISSN: 1432-072X
    Keywords: Cyanobacteria ; Ultrastructure ; Nitrogen fixation ; Water stress ; Taxonomy ; DNA ; Plasmids
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Two strains of desiccation-tolerant coccoid cyanobacteria, Chroococcus S24, a marine form, and Chroococcus N41, a cryptoendolith isolated from a hot-desert rock, have been characterized. The mol % DNA base compositions of the strains are 47.1 and 48.9% respectively. Plasmid DNA was not detected in either strain. The pigment contents and nutritional characteristics of the strains are identical. Both lack phycoerythrinoid pigments and, in culture, behave as slow-growing halotolerant marine forms with elevated requirements for Na+, Cl−, Mg2+ and Ca2+. Sucrose was the only carbon source of those tested that supported photoheterotrophic growth. Each strain synthesizes nitrogenase under anaerobic conditions but not in air. Morphologically the two strains are indistinguishable. They are considered to be independent isolates of the same cyanobacterial species. Chroococcus N41 was studied in detail with the electron microscope. When brought to equilibrium at matric water potentials of-168 MPa and lower (to-673 MPa=c0.12a w) the protoplast shrinks, but the cells maintain the same size and diameter as those at-2,156 kPa (MN medium; control); the sheath expands and remains attached to the cell wall outer membrane by fibrils. The cell wall, cell membrane, thylakoid membranes, cyanophycin granules and carboxysomes appeared intact in desiccated cells.
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    Ultrastructure of catecholamine-containing axons in the intestine of the domestic fowl (1983)
    Springer
    Cell & tissue research 234 (1983), S. 411-425 
    Details
    ISSN: 1432-0878
    Keywords: Intestines (chicken) ; Innervation ; Catecholamines ; Adrenergic fibres ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Axons in the duodenum, ileum and rectum of the domestic fowl were identified as catecholamine-containing (CA) on the basis of positive reactivity following chromaffin fixation for electron microscopy. CA-axons in association with blood vessels in all regions of the intestine and in non-vascular sites in the small intestine had a ‘ typical’ adrenergic appearance, in that they contained many small granular vesicles (SGV) and variable numbers of large granular vesicles (LGV). In the rectum the non-vascular CA-axon profiles were atypical, in that there were many elongated LGV and few SGV, and the chromaffin reactivity was weak. The nerve profiles in the rectum were dramatically reduced following 6-hydroxydopamine and reserpine treatment and were absent in rectum cultured in the absence of extrinsic ganglia. It was concluded that the profiles, in spite of their low chromaffin reactivity, truely represent CA-axons. The possibility was raised that the atypical morphology and reduced chromaffin reactivity is due to the presence of adrenaline.
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    Ultrastructural identification of corticotropes of the fetal rat (1983)
    Springer
    Cell & tissue research 234 (1983), S. 427-437 
    Details
    ISSN: 1432-0878
    Keywords: Corticotropes ; Rat fetus ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Corticotropes of rat fetuses aged 16, 18 and 21 days were localized by the indirect antibody-enzyme method on semithin sections of the pituitary. The development of the ultrastructure of these cells was observed on consecutive ultrathin sections. In comparison with previous data our present results show that identification of a fetal cell type cannot be based entirely on morphological criteria. The structural peculiarities of corticotropes obtained from studies in vivo are compared with those observed in cells maintained in vitro.
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    Cyclophosphamide-induced changes in rodent odontogenesis (1983)
    Springer
    Cell & tissue research 234 (1983), S. 679-689 
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    ISSN: 1432-0878
    Keywords: Odontogenesis ; Rats ; Cyclophosphamide ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Cyclophosphamide-induced changes in rodent odontogenesis were investigated by light and electron microscopy in four-day-old Sprague Dawley rats given one injection of 40 mg/kg of body weight of cyclophosphamide and killed at intervals of one hour, one day, one week and two weeks. Incisor and molar teeth were dissected from the animals, fixed in 2.0% glutaraldehyde in 0.1 M sodium cacodylate with 3.4% sucrose, and subsequently some were incubated for alkaline phosphatase reaction, and embedded in Spurr's medium for sectioning at light- and electron-microscopic levels. From three days a cell-sparse zone was created in the pulp in the growing end of the tooth and progressive cellular changes were observed which became more severe in the one-week and two-week specimens. Subodontoblast and adjacent pulpal cells were the most affected showing nuclear changes, damage to, or loss of, organelles, and inclusion bodies. Odontogenic epithelium was less affected and odontoblasts appeared to be unaffected by the drug. A new irregular matrix was laid down in the defect area and seemed to be the product of depolarized odontoblasts. This new matrix showed alkaline phosphatase activity, as did the cells embedded in it, and later it became mineralized. It is speculated that the polarity of odontoblasts might be maintained by an intact subodontoblastic layer; when this is lost the odontoblasts become depolarized and capable of secreting matrix from both ends.
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    Isolation of metabolically active endothelial cells in high yield from bovine cavernous bodies (1983)
    Springer
    Cell & tissue research 232 (1983), S. 579-591 
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    ISSN: 1432-0878
    Keywords: Cavernous bodies ; Endothelial cells ; Respiratory activity ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Work on endothelial cells has been limited by the availability of procedures for obtaining such cells in quantities adequate for direct in vitro analysis. The present paper describes a method for the isolation of endothelial cells from bovine cavernous bodies. A number of cells ranging from 2.5 to 4 × 108 per animal has been obtained. The cells were identified as follows 1) presence of the “Weibel and Palade” bodies in the isolated cells, 2) “cobblestone” appearance of cell cultures, and 3) presence of factor VIII, as demonstrated by immunofluorescence assays. The cell viability at the end of the purification procedure was tested 1) by dye-exclusion tests and 2) by metabolic assays. Features of this preparation are 1) the very high yield of viable endothelial cells, 2) the absence of contamination by fibroblasts and smooth muscle cells and a very low contamination by erythrocytes and 3) the fine dispersion of the isolated cells. These properties allow functional and subcellular fractionation studies on freshly isolated endothelial cells of microvascular origin.
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    Ultrastructural morphometry of the myocardium of Thunnus alalunga (1983)
    Springer
    Cell & tissue research 233 (1983), S. 427-438 
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    ISSN: 1432-0878
    Keywords: Myocardium ; Thunnus alalunga ; Ultrastructure ; Mitochondria ; Myofibrils
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The common ventricle in the heart of the Thunnus alalunga was studied. The ventricular myocardium consists of an outer compact layer and a thick inner spongy layer. The compact layer has slightly larger cells (4–6 μm diameter) than the spongy layer (2.5–5 μm diameter). Ultrastructurally the myocardium displays normal arrangements of myofibrils and mitochondria. The sarcoplasmic reticulum is poorly developed. The intercalated discs are simple with the fascia adherens being the most frequent junctional type observed; occasionally a desmosome was seen. Nexus type junctions are present but are unassociated with the intercalated discs. There are no t-tubules evident but the plasmalemma exhibits numerous caveolae which rarely form couplings with the sarcoplasmic reticulum. A morphometric analysis of the volume percent of mitochondria and myofibrils showed that the myocardial cells in the spongy layer of the heart have a significantly greater volume percentage of mitochondria than the compact layer. No significant differences were found between myocardial regions when the volume percentages of myofibrils were compared. The physiological studies revealed that the albacore tuna has heart rates (120 bpm) and ventricular blood pressures (100 mmHg) that are among the highest reported for fish.
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    Ultrastructural and immunohistochemical studies of rat epididymis (1983)
    Springer
    Cell & tissue research 233 (1983), S. 523-537 
    Details
    ISSN: 1432-0878
    Keywords: Epididymis (rat) ; Myosin ; Actin ; Fibronectin ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The anatomical distribution of smooth muscle actin, myosin, fibronectin and basement membrane has been investigated immunohistochemically, using the indirect immunofluorescence technique, in the rat epididymis. The findings were correlated with the ultrastructural organization of the organ. Actin was found to be distributed in the stereociliary region of the epithelial principal cells and in the terminal web region. Actin was also visible along the base of the epithelium. Myosin was detected in the terminal web and in the terminal bar regions of the epithelium. The contractile cells showed a strong stain for both proteins. Basement membrane immunoreactivity was distributed along the epithelial basement membrane and around the contractile cells of the wall. In the cauda, between the epithelium and the contractile cell layers, the lamina propria, containing blood vessels and a thin layer of cells, was negative for all antigens investigated. Fibronectin showed a granular distribution around the contractile cells, mainly in the cauda. The ultrastructural study showed only thin (5–6 nm in diameter) filaments in the stereocilia and terminal web region. Thin filaments were also visible in the cytoplasm of the basal cells, thus suggesting a contractile function of this cell type. The heterogeneous appearance of the contractile cells of the wall seemed to support the different contractile pattern of the epididymal regions: caput, corpus and cauda. The cells present in the lamina propria showed cytoplasmic vesicles with dark granules resembling the “A” cell granules of the endocrine pancreas and gut mucosa cells.
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    URL: http://dx.doi.org/10.1007/BF00212222
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    The structure and function of the nematocysts of Chironex fleckeri Southcott, 1956 (1983)
    Springer
    Cell & tissue research 233 (1983), S. 563-577 
    Details
    ISSN: 1432-0878
    Keywords: Nematocysts ; Structure ; Ultrastructure ; Function ; Cubozoa
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Microbasic p-mastigophores, euryteles of two size groups, holotrichous isorhizas and atrichous isorhizas, comprise the cnidom of Chironex fleckeri, a cubozoan that has been responsible for several human fatalities. In its undischarged state each microbasic mastigophore of C. fleckeri consists of a capsule containing matrix and an inverted tube possessing a smooth-walled butt which is loosely coiled helically and which narrows to form a thread that is tightly coiled helically and markedly pleated. Both butt and thread carry three helices of spines and contain a granular matrix. During discharge, the proximal butt spines form initially a piercing stylet. Granular material from the butt and thread is released prior to the release of capsular material. Each eurytele possesses a tube with a butt composed of three bulbs, the middle bulb bearing long spines. Each holotrichous isorhiza possesses a coiled tube bearing small spines along its length. Each atrichous isorhiza exhibits a tube that is devoid of spines and loosely folded in the undischarged condition. The probable role of each type of nematocyst is inferred from its structure and features that enable the ready separation of the nematocysts of C. fleckeri from those of scyphozoan jellyfish are discussed.
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    URL: http://dx.doi.org/10.1007/BF00212225
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    Ciliary epithelia of the mammalian eye in cultured explants (1983)
    Springer
    Cell & tissue research 233 (1983), S. 629-638 
    Details
    ISSN: 1432-0878
    Keywords: Ciliary process ; Cultured explant ; Epithelial cells ; Ultrastructure ; Bovine and rabbit eyes
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of ciliary epithelium from bovine, pigmented rabbit, and fetal albino rabbit were studied in cultured explants. The tips of ciliary processes were cultured in plastic dishes with Dulbecco Modified Eagle Medium (DMEM) containing 5% fetal bovine serum. More than half of the expiants adhered to the plastic culture dish, and epithelial cells spread as monolayers within a few days. Initially the explant contains two layers, the outer (nonpigmented cells) and the inner (pigmented cells). Later the explant exhibits three layers: 1) outermost lightly pigmented flattened cells, 2) an outer layer of nonpigmented cells, and 3) an inner layer of densely pigmented cuboidal cells. The cells of the outermost layer are continuous with the cells of the inner layer. A narrow space lies between the outermost layer and the outer layer. The columnar cells in the outer layer contain well developed organelles but no pigment granules; they possess a basement membrane, lateral interdigitations, and junctional complexes near their apices. Numerous focal junctions and some ciliary channel-like structures were detected between the columnar cells of the outer layer and the cuboidal cells of the inner layer. The cuboidal cells of the inner layer are filled with pigment granules. These observations suggest that the columnar cells of the outer layer are nonpigmented epithelium, the cuboidal cells of the inner layer are pigmented epithelium, and the flatened cells in the outermost layer are derived from pigmented epithelium.
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    URL: http://dx.doi.org/10.1007/BF00212230
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    Ultrastructural observations on the formation of follicles in the human fetal thyroid (1983)
    Springer
    Cell & tissue research 233 (1983), S. 693-698 
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    ISSN: 1432-0878
    Keywords: Thyroid gland ; Human fetus ; Follicles ; Ultrastructure ; Differentiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Thyroid glands from 40 human fetuses ranging from 30 to 175 mm in length were examined by electron microscopy. At the 30 mm stage, the cells are arranged in cords or clusters and contain numerous free ribosomes. The rough-surfaced endoplasmic reticulum (RER) is poorly developed and the Golgi complex consists of saccules, smooth and coated vesicles. Mitochondria, microfilaments, glycogen particles, occasional lysosome-like structures, and single cilia are observed. At sites of incipient follicle formation, intercellular clefts containing interdigitating microvilli, delimited by junctional complexes, are evident. In addition, the apical region of some cells contains vacuoles. At the 50-mm stage, intercellular clefts are more apparent, some of them organized into small follicles through the enlargement of the lumen, the incorporation of additional cells, and the formation of a basal lamina. With increasing gestational age, more follicles are established. The lumina vary from round to clover-leaf shaped and have an electron-dense content. Cisternae of RER are dilated and contain flocculent material. The Golgi complex is more extensive, and lysosome-like structures are more numerous. By the 100-mm stage, the follicular cells appear morphologically well differentiated. The results demonstrate an extracellular origin of the follicular lumen in the human fetal thyroid.
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    URL: http://dx.doi.org/10.1007/BF00212236
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    Ultrastructural immunocytochemical localization of fibronectin in the developing rat lung (1983)
    Springer
    Cell & tissue research 234 (1983), S. 165-177 
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    ISSN: 1432-0878
    Keywords: Fibronectin ; Lung ; Development ; Ultrastructure ; Immunocytochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In a previous study changes in the macrodistribution of fibronectin during rat-lung development were examined. Using the peroxidase-antiperoxidase immunocytochemical technique, we have demonstrated the presence of fibronectin in embryonic, neonatal, and adult rat lung at the ultrastructural level. In the embryo, fibronectin is found both in an intra-and extracellular association with isolated pneumoblasts, and in a periodic distribution along the basal lamina. The neonate displays fibronectin in an intracellular association with early type-I cells and on their basal and luminal surfaces, but not in association with type-II cells. Neonatal basal lamina is diffusely labeled by anti-fibronectin antiserum. Fibronectin in adult tissue is found both intracellularly and on the basal and luminal surfaces of type-I cells but not in type-II cells. The basal lamina and interstitial connective tissue are slightly or non-reactive. These observations confirm and extend our initial suggestion that fibronectin is involved in rat-lung development.
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    URL: http://dx.doi.org/10.1007/BF00217410
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    Electron microscopy of extracellular materials during the development of a sea star, Patiria miniata (Echinodermata: Asteroidea) (1983)
    Springer
    Cell & tissue research 234 (1983), S. 193-200 
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    ISSN: 1432-0878
    Keywords: Sea star ; Development ; Cuticle ; Extracellular materials ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The fine structure of conspicuous extracellular materials during the life history of a sea star (Patiria miniata) is described. The outer surface of the developing sea star is covered by two morphologically different cuticles that appear sequentially during ontogeny. The primary cuticle, which is about 120 nm thick and two-layered, is present from mid-blastula through the end of the larval stage. The secondary cuticle, which is about 1 μm thick and three-layered, first appears on the epidermis of the rudiment region of the larva and, after metamorphosis, covers the entire epidermis of the juvenile and adult stages. During ontogeny, there are only two conspicuous gut cuticles: the first lines the newly invaginated archenteron at the start of the gastrula stage, and the second lines the esophagus during the larval stage. A blastocoelic basal lamina first appears at mid-blastula and persists as subectodermal and subendodermal basal laminae. Ruthenium red-positive granules are detectable between the lateral surfaces of adjacent ectodermal cells during part of the gastrula stage; this transient intercellular material may possibly aid in lateral adhesion between cells.
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    URL: http://dx.doi.org/10.1007/BF00217412
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    Changes in plastid ultrastructure during iron nutrition-mediated chloroplast development (1983)
    Springer
    Protoplasma 114 (1983), S. 85-92 
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    ISSN: 1615-6102
    Keywords: Chloroplasts ; Iron stress ; Sugar beet ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary When grown in iron-free media, the youngest leaves of healthy green sugar beet plants became completely yellow after 6 to 8 days. This chlorosis was quickly reversed by resupplying iron. A study of the ultrastructure of the iron -stressed leaves revealed apparently normal subcellular organization except for the plastids which were small and undeveloped, contained a rudimentary, disorganized grana-fretwork and clusters of vesicles in the periphery. Twelve to 16 hours after resupply of iron, aggregates of phytoferritin were observed in the stroma, and the granal fretwork underwent further development. There was an increased orientation of the membranes along the long axis of the plastids and an increase in the length of the individual grana stacks. By 48 hours, leaf chlorophyll content was about 40% of the control. At the ultrastructural level, parallel alignment of membrane orientation was complete and the grana stacks began to increase in the number of thylakoids per stack.
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    URL: http://dx.doi.org/10.1007/BF01279871
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    Nucleolus-associated bodies (karyosomes) in dividing and differentiating plant cells (1983)
    Springer
    Protoplasma 115 (1983), S. 1-10 
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    ISSN: 1615-6102
    Keywords: Brassica napus ; Nucleolus ; Pisum sativum ; Ultrastructure ; Zea mays
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The karyosome is a spherical body up to 1 μm in diameter that lies on the nucleolus of certain plant species, particularly those with a relatively low nuclear DNA content and an areticulate nuclear structure. It can be seen in the light microscope after impregnation with silver; in the electron microscope its structure consists of fibrillo-granular material. Nucleoli of cells in root apices may bear 0, 1, or 2 karyosomes. The frequency with which these numbers of karyosomes are observed depends on the location of the cells within the apex. In roots ofPisum sativum andZea mays the nucleoli of both slowly-dividing and young differentiating cells bear karyosomes more frequently than the nucleoli of rapidly-dividing cells. The karyosome seems to adopt a preferred location on the nucleolus, lying most frequently on the nucleolar surfaces directed towards the apex or base of the root. The origin and functional significance of the karyosome are discussed. Morphological evidence suggests that it may be material that formerly was part of a fibrillar centre.
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    URL: http://dx.doi.org/10.1007/BF01293574
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    Stomatal pore and cuticle formation inFunaria (1983)
    Springer
    Protoplasma 116 (1983), S. 1-13 
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    ISSN: 1615-6102
    Keywords: Cuticle ; Peristomatal transpiration ; Stomata ; Ultrastructure ; Funaria
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cuticle and pore development in the guard cells ofFunaria were investigated with the electron microscope. Pore cuticle formation is simultaneous with the creation of the pore itself. The morphology of the pore cuticle is unlike that of any cuticle described in the literature. It has many lamellae which are penetrated by electron dense fibrils. Three different cuticular morphologies exist from the pore to the subsidiary cell walls. The cuticles on the pore and outer walls contain fibrils that sometimes reach to the surface. The subsidiary cell cuticle lacks fibrils altogether. It is hypothesized that (1) cuticularization of the middle lamella contributes to ventral wall separation and (2) differences in extent of cuticular fibrils are related to greater water loss from stomata than from subsidiary cells (peristomatal transpiration).
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    URL: http://dx.doi.org/10.1007/BF01294225
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    Microtubule organization and morphogenesis in young spores of the mossTetraphis pellucida Hedw (1983)
    Springer
    Protoplasma 116 (1983), S. 115-124 
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    ISSN: 1615-6102
    Keywords: Microtubules ; Moss ; MTOC ; Sporogenesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Microtubule systems appear sequentially at the distal and proximal poles of tetrad members during mid-sporogenesis in the mossTetraphis pellucida Hedw. The distal microtubule system emanates from a microtubule organizing center (MTOC) located between the single plastid and the nucleus. The distal MTOC and associated microtubules, which appear immediately after cytokinesis, are ephemeral and do not appear to be associated with the deposition of exine occuring at the same time. The proximal microtubule system, which appears slightly later than the distal system, is a more stable component of mid-sporogenesis. The proximal MTOC is an irregularly lobed, patelliform aggregation of electron-dense granules located beneath the plasma membrane at the proximal spore pole. Several bundles of microtubules radiate from the proximal MTOC and traverse the cell, enclosing the nucleus in an cone of microtubules. The proximal microtubule system is thought to function in aperture development and organelle migration. The relatively large nucleus migrates a short distance in the small spore early in the tetrad stage and maintains its acentric position at the proximal pole throughout later stages of sporogenesis. The plastid migrates later in the tetrad stage from its meiotic position parallel to the distal surface to a position perpendicular to the distal surface with one tip in close proximity to the proximal MTOC. The proximal microtubule system reaches its maximum development by the end of the tetrad stage and all micrographic evidence of it is lost in the maturation stages of late sporogenesis.
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    URL: http://dx.doi.org/10.1007/BF01279828
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    Morphogenesis of coremia and rhizomorphs in the AscomyceteSphaerostilbe repens (1983)
    Springer
    Protoplasma 116 (1983), S. 99-114 
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    ISSN: 1615-6102
    Keywords: Sphaerostilbe repens ; Ultrastructure ; Differentiation ; Coremia ; Rhizomorphs
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The differentiating stages of coremia and rhizomorphs inSphaerostilbe repens were studied by transmission electron microscopy. Vegetative mycelium is characterized by highly cytoplasmic cells rich in ribosomes and mitochondria and with few vacuoles as well as endoplasmic reticulum. Cell walls are thin attaining a maximum thickness of 0.10 μm. During the aggregating phase a prosenchymatous mass of randomly oriented cells is produced by localized elongation and branching of the filaments. The hyphae in this region have the appearance of actively metabolising cells. In the course of the differentiating phase, numerous hyphae of the median zone of the aggregate grow upward and downward to give rise to coremium and rhizomorph primordia respectively. The individual hyphal tips lay parallel to each other and cells of the growing apices retain their meristematic characteristics. At the periphery of the aggregate and to a lesser extent in the subapical rhizomorphic zone, cells reduce their cytoplasmic density as a consequence of a decrease in the number of ribosomes. These cells also increase in size and become isodiametric and vacuolated. During cellular differentiation walls increase steadily in thickness and at the elongating phase they reach 0.30 μm in the rhizomorphic cortex. Mucilaginous material is progressively deposited around hyphae and in the most differentiated zones, coalesce to fill interhyphal spaces. This extracellular matrix seems to play a role in maintaining cohesiveness of the aggregated organs. The tissue in the process of differentiation is scattered with cells highly enriched in mitochondria and with cells virtually undifferentiated. Accumulation of microfilaments takes place in the differentiating zone localized behind the immersed meristematic apex. These structures might be involved in wall synthesis. Glycogen rosettes accumulate in the vegetative mycelium surrounding the aggregating centers, suggesting the possibility of supplying energy during the differentiating processes. The vacuolar system, represented by autophagic vacuoles which are present until the differentiation phase, presumably may also participate in the biochemical changes that occur during aggregation. Coremial cells are characterized by an increase in wall thickness, a highly sinuous plasma-membrane as well as large amounts of mucilaginous compounds accumulated between hyphae, but in all other respects they resemble the cells of actively growing vegetative hyphae.
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    Ultrastructure of aerial stalk formation by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 125-135 
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    ISSN: 1615-6102
    Keywords: Ciliated protozoan ; Sorogenesis ; Extracellular matrix ; Secretion ; Extrusive organelles ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Sorogena stoianovitchae Bradbury andOlive is an unusual kinetophragminophoran ciliate characterized by the aggregation of individual trophic cells to form a multicellular sorogen that rises aerially from the medium surface to produce a sorocarp. A light and electron microscope study of sorogenesis revealed how the sorogenic cells produce the stalk. The feeding ciliates contain numerous subpellicular expansions of rough endoplasmic reticulum cisternae that are only one element of the secretory system necessary for stalk formation. Upon aggregation, the stalk secretory system develops further, initially with the proliferation of the subpellicular expansions. Then, during later aggregation and early sorogenesis, other secretory elements appear: stalk material vesicles, dense granule vesicles, and electron lucent vacuoles. These are all derived from the rough endoplasmic reticulum. Only the subpellicular expansions and stalk material vesicles appear to add to the stalk matrix. The dense granule vesicles could be precursors of the stalk material vesicles; the electron lucent vacuoles, which can be demonstrated to contain fibrillar material, are perhaps by-products of the secretory process. Sorogenesis inSorogena occurs by a mechanism unique among the stalk-producing protists that have been studied.
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    URL: http://dx.doi.org/10.1007/BF01279829
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    Stalk function during sorogenesis by the ciliated protozoanSorogena stoianovitchae (1983)
    Springer
    Protoplasma 116 (1983), S. 136-144 
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    ISSN: 1615-6102
    Keywords: Stalk ; Ciliated protozoan ; Sorogenesis ; Extracellularmatrix ; Ultrastructure ; Secretion
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The sorogenic cells of the haptorid ciliateSorogena stoianovitchae Bradbury andOlive secrete a hydrated, fibrillar matrix that becomes organized to form a stalk. This light and electron microscope study examines the role of the secreted stalk matrix in the development of the sorocarp. The stalk material is secreted as a compact clump or clumps of material that expands as it hydrates. The expanded stalk material is initially viscous, but soon, through dehydration or cross-linking, solidifies to form a sheath. The sheath is the outside layer of the stalk, provides structural support, and controls the expansion of the newly secreted stalk material. The sorogenic cells continue to secrete stalk material that expands once it is outside of the cell. The resulting expansion force is directed upward by the sheath, thereby moving the cells further above the surface. The continued dehydration of the sheath material provides an inwardly directed force that also contributes to the upward movement of the sorogen.
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    Ultrastructural demonstration of loss and recovery of cytochrome oxidase activity during and after heat induction of microcycle conidiation inNeurospora crassa (1983)
    Springer
    Protoplasma 116 (1983), S. 149-154 
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    ISSN: 1615-6102
    Keywords: Cytochrome oxidase ; Cytochemistry ; Ultrastructure ; Neurospora ; Heat treatment
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytochrome oxidase (EC 1.9.3.1) activity of conidia of wild-typeNeurospora crassa was detected cytochemically at the ultrastructural level by 3,′-diaminobenzidine (DAB) reaction during heat treatment at 46 °C and after shift down to 25 °C. At 46 °C the decrease in the enzyme activity was shown to be time-dependent (0–10 hours) in the progressively overswelling conidia. Gradual recovery of the DAB reaction occurred in mitochondria of conidia outgrowing conidiogenous germ tubes (microcycle conidiation) when shifted down to 25 °C. Inactivation of cytochrome oxidase was efficiently prevented during heat treatment in the presence of Tween 20. Such conidia no longer overswelled but still required shift down to 25 °C to produce germ tubes with delayed conidiogenous ability.
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    URL: http://dx.doi.org/10.1007/BF01279832
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    The effect of UV-B and UV-C radiation on sugar beet leaves (1983)
    Springer
    Protoplasma 117 (1983), S. 7-16 
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    ISSN: 1615-6102
    Keywords: Beta vulgaris ; Chloroplast ; Ultrastructure ; Ultraviolet radiation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effect of UV-C (254 nm) and UV-B (290–320 nm) radiation on leaves ofBeta vulgaris L. at the ultrastructural level was investigated. Although the damage caused by UV-C radiation was more striking than that resulting from UV-B radiation, several structural changes were seen in the UV-B treated material. Generally the effects of UV-B and UV-C radiation were different, suggesting different mechanisms of action, discernible even at the ultrastructural level.
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    URL: http://dx.doi.org/10.1007/BF01281779
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    The ultrastructure of the formation and development of the amoeboid tapetum inArum italicum miller (1983)
    Springer
    Protoplasma 117 (1983), S. 116-129 
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    ISSN: 1615-6102
    Keywords: Pollen ; Amoeboid tapetum ; Arum italicum ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary A tapetum is found around all higher plant meiocytes and is thought to nourish them. It may, in turn, be influenced by their development. The mature tapetal membrane in amoeboid (or periplasmodial) tapeta, of whichArum italicum is an example, fits closely around the developing meiocyte. This description of tapetal ultrastructure starts from the meiotic prophase when the tapetum is still cellular and comprises two rows of cells on the inside of the tetrasporangiate anther. The radial walls of the still cellular tapetum start to dissolve during leptotene of the first meiosis. The lysis begins in the middle lamella in those areas penetrated by the most plasmodesmata. The walls in contact with the meiocytes on the other hand do not disappear until after the first meiosis. At telophase the now fused cytoplasmic tapetal mass begins to extend its joint plasmamembrane, amoeboid fashion, into the loculus. A cluster of microtubules can be seen at the apex of this intrusion apparently initiating or maintaining the shape of the invading plasmamembrane front. The tapetum now adheres closely to the microspores. The tapetal zone closest to the spores has a prominent population of microtubules and just a little ER, whereas the outer zone away from the spores contains all the other organelles. The inner zone, in a squash preparation, is not readily separated from the spores. The microtubules, at the middle microspore stage, are no longer to be seen in a circle around the microspores, but spread out with some lying orthogonal to the now-forming exine surface. In places the tapetal plasmamembrane begins to retract from the exine leaving roughly cone-shaped zones (spines) which become filled with fibrillar material. This material begins to be deposited on the exine surface. These “spines” are both PAS. and Coomassie-blue positive and susceptible to acetolysis.
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    The structure and histochemistry of sclerotia ofSclerotinia minor Jagger III. Changes in ultrastructure and loss of reserve materials during carpogenic germination (1983)
    Springer
    Protoplasma 117 (1983), S. 214-225 
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    ISSN: 1615-6102
    Keywords: Histochemistry ; Sclerotia ; Sclerotial germination ; Sclerotinia ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Cytoplasmic reserves and extracellular substances were progressively broken down and utilized during carpogenic germination of sclerotia ofSclerotinia minor. Glycogen, wall polysaccharides and polyphosphate granules were removed first from regions of the sclerotium distant from developing apothecia, while protein bodies near the base of apothecial stipes were hydrolysed before those further away. The number of profiles of mitochondria and endoplasmic reticulum in cortical and medullary hyphae increased at the onset of germination, indicating increased metabolism in the hyphae. In contrast to developing sclerotia, simple pores with Woronin bodies were frequent in walls and septa during germination. Hyphae that appeared to converge towards the base of apothecial initials retained their cytoplasm and organelles until late in germination and hydrolysis of their reserves was delayed; these are interpreted as translocatory hyphae, although further work is required to determine their role unequivocally. When apothecia were fully developed, hyphae throughout the sclerotium were empty and the walls and extracellular matrix of cortical and medullary hyphae had almost completely broken down.
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    URL: http://dx.doi.org/10.1007/BF01281825
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    Mitosis in the freshwater red algaBatrachospermum ectocarpum (1983)
    Springer
    Protoplasma 118 (1983), S. 56-70 
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    ISSN: 1615-6102
    Keywords: Carposporophyte ; Cell division ; Mitosis ; Rhodophyta ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Mitotic ultrastructure was observed in meristematic cells of carposporophyte generations of the freshwater red algaBatrachospermum ectocarpum. Prior to nuclear division, cell elongation occurs resulting in the nucleus being located at the proximal end of the cell and separated by a large central vacuole from a distal “empty region” which the daughter nucleus eventually occupies. In late prophase, nuclear envelope-attached polar rings are situated adjacent to shallow nuclear invaginations. At prometaphase the nuclear invaginations extend deeply into the nucleus forming continuous cytoplasmic channels containing microtubules. Perinuclear ER and a typical equatorial chromosomal plate are formed by metaphase at which time the nuclear envelope lining the cytoplasmic channels has dispersed. Chromosomal and non-chromosomal microtubules converge at the poles where a single, large gap is seen in the otherwise intact nuclear envelope. Polar rings were not detected in the few mitotic cells observed beyond prometaphase but are thought to be present. During anaphase an interzonal midpiece is formed and the distal-most incipient daughter nucleus moves laterally past the central vacuole into the apical “empty region”. Features of mitosis inBatrachospermum are believed to be intermediate between those exhibited by the lower and higher orders of red algae, this being consistent with the taxonomic placement of the genus in theNemaliales, the least advanced order of the classFlorideophyceae.
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    The ultrastructure of nuclear bodies in interphase plant cell nuclei (1983)
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    Protoplasma 118 (1983), S. 95-103 
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    ISSN: 1615-6102
    Keywords: Nuclear bodies ; Nucleolus ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Nuclear bodies are found in interphase nuclei of root apices of a number of plant species. They often show differences in structure and position relative to the nucleolus and this has led to an attempt to define two classes of body. However, in some species their separation into two classes on structural grounds alone breaks down, indicating that although they may occupy different positions within the nucleus they may in these particular cases be only different forms of the same body. The two extremes of the range of bodies examined represent what have been called “nucleolus-associated body” (karyosome) and “dense body”. The nucleolus-associated body is typically attached to, or adjacent to, the nucleolus. It is composed of fibrils 4–8 nm wide and often has an open structure showing compound threads or fibrils separated from each other by electron-lucent spaces. The dense body is more compact in structure and typically lies free in the nucleoplasm. Both types of body have an affinity for silver ions which, together with their staining reaction following treatment with EDTA, indicates that they consist of ribonucleoprotein. The characteristics of nuclear bodies found in different plant species have some relationship with the structure and DNA content of the interphase nucleus. Nucleolus-associated bodies are characteristic of species with an areticulate nuclear structure (2 C DNA content 〈6 pg), while dense bodies are common in species with a reticulate nuclear structure (2 C DNA content 〉6 pg). The possible functions of the two forms of nuclear body are discussed.
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    URL: http://dx.doi.org/10.1007/BF01293065
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    Ultrastructural polysaccharide localization in calcifying and naked cells of the coccolithophoridEmiliania huxleyi (1983)
    Springer
    Protoplasma 118 (1983), S. 157-168 
    Details
    ISSN: 1615-6102
    Keywords: Calcification ; Coccolithophorids ; Polysaccharide localization ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Emiliania huxleyi is a marine coccolithophorid which produces coccoliths,i.e., particles consisting of calcite and macromolecular organic material. The coccoliths are formed intracellulary in specialized organelles which comprise a coccolith vesicle (CV) and a reticular body (RB), together forming the CV/RB system or calcifying system. After termination of calcification, the coccolith is extruded and incorporated into the coccosphere,i.e., one or several layers of extracellular coccoliths surrounding the cell. Apart from the coccolith-producing cells (C cells) ofE. huxleyi, there are naked cells (N cells) which seem to have lost the capacity to produce coccoliths but are very similar to the C cells in other morphological respects. Biochemical studies have revealed that polysaccharides may play a regulatory role in calcification. The aim of the present study was to determine the localization of polysaccharides in both C and N cells electron microscopically. For this purpose, a cytochemical staining technique according toThiéry (1967) was applied. The CV/RB system of C cells was conspicuously stained. Due to the excellent stainability of this system, a putative succession of morphological stages during coccolithogenesis could be described. The staining pattern of the N cells closely resembled that of the C cells. It was found, however, that the “calcifying” system of N and C cells differed in both morphology and position. It is suggested that the divergent morphology of the “calcifying” system of N cells accounts for its failure to produce coccoliths.
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    URL: http://dx.doi.org/10.1007/BF01293073
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    Some aspects of the development of the endodermis and cortex ofTilia cordata andPicea sitchensis (1983)
    Springer
    Plant and soil 71 (1983), S. 147-153 
    Details
    ISSN: 1573-5036
    Keywords: Cortex ; Endodermis ; Picea sitchensis ; Tilia cordata ; Transfer cells ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Summary The endodermis of bothTilia cordata andPicae citchensis progressess through 3 characteristic phases of development. These developments are delayed somewhat in the xylem pole endodermis ofT. cordata, while inP. sitchensis 3–5 passage cells are found. The cortex ofT. cordata is characterised by very thick walls, while that ofP. sitchensis is characterised by a thick walled layer just outside the endodermis and by 2–3 outer layers of transfer cells.
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    URL: http://dx.doi.org/10.1007/BF02182649
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    Ultrastructure of trout spermatozoa: Changes after dilution and deep-freezing (1983)
    Springer
    Cell & tissue research 228 (1983), S. 205-218 
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    ISSN: 1432-0878
    Keywords: Spermatozoa ; Ultrastructure ; Deep-freezing ; Sperm manipulation ; Trout
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Trout spermatozoa taken from the testis, vas deferens and ejaculate are described at the ultrastructural level. The morphology of the spermatozoa head, changes in the middle-piece structure, and the relationship between the centrioles and the flagellum were studied under consideration of their role in the reproduction of this species. Morphological changes observed after dilution of the spermatozoa in freshwater or saline and subsequent freezing deserve attention in connection with certain manipulations used in fish farms and laboratories.
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    URL: http://dx.doi.org/10.1007/BF00204873
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  • 77
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    Circadian variations in pinealocytes of the Chinese hamster, Cricetulus griseus (1983)
    Springer
    Cell & tissue research 228 (1983), S. 231-244 
    Details
    ISSN: 1432-0878
    Keywords: Pineal gland ; Circadian rhythm ; Synaptic ribbon ; Ultrastructure ; Chinese hamster (Cricetulus griseus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Circadian morphological variations of pinealocytes in the superficial pineal of the Chinese hamster (Cricetulus griseus) were studied using quantitative electron-microscopic techniques. The volume of the nucleus and cytoplasm of pinealocytes exhibited similar circadian variations, with the maximum around the middle of the light period and the minimum during the first half of the dark period. Synaptic ribbons in pinealocytes were classified into three groups, type-1, −2 and −3 synaptic ribbons, which appeared as rods, round or irregular bodies and ring-shaped structures, respectively; a synaptic ribbon index was determined for the respective types. The synaptic ribbon index was expressed as the number of synaptic ribbons in the pinealocyte profile representing the cell size. The type-1 synaptic ribbon index, which was smallest during the second half of the light period, was increased during the dark period. The length of straight or slightly curved rods showed a 24-h change similar to that of the type-1 synaptic ribbon index; the length of the rods was maximal during the first half of the dark period and minimal at the end of the light period. There was no apparent circadian variation in the type-2 synaptic ribbon index. The type-3 synaptic ribbon index was higher during the light period than during the dark period; the index attained zero 3h after the onset of darkness and, thereafter, increased gradually.
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    URL: http://dx.doi.org/10.1007/BF00204875
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    Immunocytochemical localization of enkephalin in the lateral septum of the guinea-pig brain (1983)
    Springer
    Cell & tissue research 228 (1983), S. 265-276 
    Details
    ISSN: 1432-0878
    Keywords: Met- and leu-enkephalin ; Immunocytochemistry ; Ultrastructure ; Lateral septum ; Guinea-pig brain
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary By the use of antisera to met-enkephalin and leu-enkephalin, enkephalin-containing structures were visualized in the lateral septum of the guinea-pig brain. The present results do not reveal immunoreactive perikarya in this area. The immunostaining is exclusively located in numerous nerve fibers and endings mostly encompassing neuronal perikarya, which accounts for the fact that at the light-microscopic level cellular somata appear to be immunostained. The immunoreactive terminals and fibers contain granules approximately 110nm in diameter and synaptic vesicles. The origin and the functional role of these numerous enkephalin terminals remain to be established. This work was supported by a grant from INSERM N∘ 804012
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    URL: http://dx.doi.org/10.1007/BF00204878
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    The effects of colchicine on the distribution of glycoprotein-containing vesicles in epithelial cells of the murine colon (1983)
    Springer
    Cell & tissue research 228 (1983), S. 323-335 
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    ISSN: 1432-0878
    Keywords: Ultrastructure ; Colonic epithelium ; Colchicine ; Vesicles ; Glycoproteins
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In murine colonic epithelial cells, cell-coat glycoproteins are transported to the cell surface in vesicles that originate at the Golgi apparatus. To determine the role of microtubules in the movement of these vesicles the antimicrotubule agent colchicine was injected into mice at several time intervals prior to sacrifice. In the mice that were treated with colchicine for 4.5 h it was observed that the polarity of the cells was disturbed. The Golgi apparatus and nucleus often appeared interchanged in their positions. The glycoprotein-containing vesicles, normally located apically, were sparse in that location, but abundant near the lateral plasma membranes of the cells at the level of the nucleus and Golgi apparatus. Staining by the periodic acid-chromic acid-silver methenamine technique for glycoproteins clearly revealed the reduction of vesicles apically and accumulation of vesicles laterally. The mechanism responsible for the movement of the vesicles to this location is unclear. It is suggested that the accumulation of vesicles in the lateral region may reflect some hindrance in the fusion of the vesicles with the lateral cell membranes.
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    URL: http://dx.doi.org/10.1007/BF00204882
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    Structure of the non-lymphoid cells during the postnatal development of the rat lymph nodes (1983)
    Springer
    Cell & tissue research 229 (1983), S. 219-232 
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    ISSN: 1432-0878
    Keywords: Lymph nodes ; Postnatal development ; Fibroblastic reticulum cells ; Interdigitating cells ; Deep cortex units ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary This study describes the postnatal development of the nonlymphoid cells with special reference to the fibroblastic reticulum cells (FRCs) and interdigitating cells (IDCs). The first lymphocytes of the neonatal lymph nodes are located in the developing deep cortex units (DCUs) identified by the Gomori's technique for reticulin fibres. Ultrastructural studies demonstrate that FRCs form the stroma of the DCUs. By light and electron microscopy, it is demonstrated that FRCs occupy the outer cortex in the following stages of development of the lymph nodes. Thus, FRCs form the stroma of the primary follicles and, later, are transformed in follicular dendritic cells (FDCs) of the germinal centres. Immature or pro-IDCs appear as migrating elements in the deep cortex of lymph nodes of the neonatal rats. The ultrastructure of the pro-IDCs resembles that of the mature IDCs but not that of the phagocytic cells. Pro-IDCs are transformed into mature IDCs whose cytoplasmic expansions contact lymphocytes via tight junctions. Some of these lymphocytes are likely apposed to FRCs of the DCUs. No cells containing Birbeck granules were found in the parenchyma of the lymph nodes during the postnatal development. The role of these nonlymphoid cells is discussed with respect to the immunologic function of mammalian lymph nodes.
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    URL: http://dx.doi.org/10.1007/BF00217894
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    Cytodifferentiation of the paraventricular nucleus in the chick embryo (1983)
    Springer
    Cell & tissue research 229 (1983), S. 281-297 
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    ISSN: 1432-0878
    Keywords: Paraventricular nucleus ; Hypothalamus ; Development ; Golgi study ; Ultrastructure ; Chick embryo
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The developmental changes in the cytoarchitecture of the hypothalamic paraventricular nucleus of the chick embryo were studied with particular emphasis on the differentiation of the magnocellular neurons. These cells can be distinguished from the parvocellular elements starting from stages 34–35 (Hamburger and Hamilton 1951) in Golgi-impregnated specimens. At the same stages, electron microscopy reveals dense-core granules, resembling the characteristic elementary granules of the neurosecretory material in the cytoplasm of the larger neurons. In addition, a few immature synapses were observed on these magnocellular perikarya. The present observations suggest that the early onset of neurosecretion in this area may be neurally regulated during early phases of development.
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    Putative sense organs on the palliai tentacles of the limpet, Patella vulgata (L.) (1983)
    Springer
    Cell & tissue research 231 (1983), S. 663-674 
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    ISSN: 1432-0878
    Keywords: Ciliary tuft ; Pallil tentacles ; Patella vulgata ; Sensory ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure and ultrastructure of ciliary tufts on the pallil tentacles of the limpet Patella vulgata (L.) are described. The tip of each tentacle is covered by a dense crown of tufts and additional tufts can be seen scattered evenly across the surface of each tentacle. The cilia are nonmotile and nerve fibres run from the base of the ciliated cells suggesting a sensory function. Comparisons are made with ciliary tufts found in a Pacific species of limpet, Acmaea scutum, and other molluscan sensory structures.
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    URL: http://dx.doi.org/10.1007/BF00218124
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    Structural studies of the adrenal zona glomerulosa and renal juxtaglomerular apparatus in pregnant sheep (1983)
    Springer
    Cell & tissue research 232 (1983), S. 177-187 
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    ISSN: 1432-0878
    Keywords: Pregnancy ; Adrenal zona glomerulosa ; Juxtaglomerular apparatus ; Ultrastructure ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural changes in the adrenal zona glomerulosa and renal juxtaglomerular apparatus have been examined during normal pregnancy in sheep. As pregnancy progressed, increasing numbers of cells in the adrenal zona glomerulosa displayed mitochondria with straight tubular “rod-like” structures replacing their normal lamelliform cristae; groups of cells showing these mitochondrial changes were predominantly located in the middle and superficial regions of the zona glomerulosa, but at all stages remained interspersed with cells with apparently normal mitochondria. In the same animals, the renal juxtaglomerular index was raised, reflecting an increase in renin storage, and juxtaglomerular myoepithelioid cells showed increased numbers of cytoplasmic granules, but no apparent increase in granular endoplasmic reticulum and Golgi profiles; there were no distinguishing morphological changes in juxtaglomerular peripolar cells. These findings provide morphologic evidence of stimulation of the adrenal zona glomerulosa in association with increased juxtaglomerular renin storage during pregnancy. The mitochondrial changes observed in an increasing proportion of cells in the zona glomerulosa closely resemble those seen in sodium-depleted animals, and may reflect the altered steroidogenic capacity of the adrenal gland in pregnant sheep. The finding of groups of cells displaying altered mitochondria lying next to cells with normal mitochondria suggests the presence of cells with different sensitivities to stimuli for aldosterone production or may indicate the presence of different cell types in the zona glomerulosa responding to different stimuli.
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    URL: http://dx.doi.org/10.1007/BF00222382
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    The ultrastructure of oesophageal striated muscle in the guinea-pig and marmoset (1983)
    Springer
    Cell & tissue research 234 (1983), S. 365-376 
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    ISSN: 1432-0878
    Keywords: Oesophageal striated muscle ; Ultrastructure ; Guinea-pig, marmoset
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructural characteristics of oesophageal striated muscle from guinea-pig and marmoset have been examined using transmission electron microscopy and compared with ultrastructural features of skeletal muscle. The findings show that, although similar to skeletal muscle, oesophageal striated muscle exhibits important differences in the arrangement of its muscle fibres and their motor innervation. It was also found impossible to classify oesophageal striated muscle according to the usual ultrastructural criteria since its motor endplates bore a greater resemblance to those of intrafusal skeletal muscle fibres. The consideration of these differences in conjunction with characteristics revealed elsewhere by other techniques confirms the unique nature of oesophageal striated muscle.
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    URL: http://dx.doi.org/10.1007/BF00213774
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    Structure of the pars distalis in the adult tammar wallaby (Macropus eugenii) (1983)
    Springer
    Cell & tissue research 229 (1983), S. 155-174 
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    ISSN: 1432-0878
    Keywords: Pituitary ; Tammar wallaby ; Marsupialia ; Ultrastructure ; Immunohistochemistry ; Cell types
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary An immunohistochemical, light- and electron-microscopial study was made of the pars distalis in adult tammar wallabies (Macropus eugenii). The pars distalis of this marsupial mammal was divided into three regions, based on the distribution of cell types within the gland. Somatotropic, mammotropic, luteotropic, folliculotropic, corticotropic and thyrotropic cells were identified on the basis of their immunohistochemistry, cytology and ultrastructure. Non-granulated (folliculo-stellate) cells, identified in electron micrographs, were found throughout the pars distalis. Somatotropic cells were predominant in the posterior pars distalis in all animals examined. In the single male specimen and in the non-lactating females examined, small numbers of apparently inactive mammotropic cells were scattered throughout the pars distalis; the same cell type was apparently active and present in considerable numbers in lactating females. Only one morphological type of gonadotropic cell was evident; these cells were scattered throughout the pars distalis, but in largest numbers in the median region. Small numbers of thyrotropic cells were found, most commonly in the anterior pars distalis. Corticotrops were also observed in moderate numbers, predominantly in the anterior regions of the pars distalis.
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    Ultrastructure of sensilla on the antennal pedicel of the brown planthopper Nilaparvata lugens Stal (Insecta: Homoptera) (1983)
    Springer
    Cell & tissue research 228 (1983), S. 313-322 
    Details
    ISSN: 1432-0878
    Keywords: Olfactory ; Sensilla ; Ultrastructure ; Insects
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Scanning- and transmission electron-microscope studies of the sensilla of the pedicel of Nilaparvata lugens have revealed an elaborate plaque organ and three structurally different types of trichoid hairs. Each plaque organ is innervated by 120–150 neurons arranged in groups. The porous sensory cuticle is folded into finger-like projections and is surrounded by protective non-sensory denticles. Trichoid sensilla differ in number of neurons, appearance of dendrites and arrangement of pores. Type I, innervated by 2 neurons, has pores along its length and is probably olfactory in function. Types II and III are innervated by one and five neurons, respectively, and the absence of pores along the hair shaft indicates a possible gustatory role. The importance of these sensilla is discussed with reference to the behaviour of this important insect pest.
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    URL: http://dx.doi.org/10.1007/BF00204881
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    Topography, ultrastructure and phagocytic capacity of avian lymph nodes (1983)
    Springer
    Cell & tissue research 228 (1983), S. 389-403 
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    ISSN: 1432-0878
    Keywords: Lymph node, avian ; Ultrastructure ; Macrophages ; Phagocytic capacity
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The structure of the avian lymph node (ALN) is characterized by a thin capsule, thin lymphoreticular cords, and an absence of trabeculae. It is not possible to subdivide the ALN into cortex, paracortex and medulla, or to subdivide the system of sinuses into marginal, trabecular and medullary divisions. The lymphoreticular cords contain avian germinal centers (AGC) with B-lymphocytes and the area of T-lymphocytes. Postcapillary venules are responsible for the recirculation of lymphocytes. Sinus reticular cells do not exist in the ALN, but free macrophages are present. The phagocytic capacity of the macrophages was determined by injection of vital dyes (India ink, Berlin blue) and inoculation with Candida cells. Macrophages filled with markers migrate from the lymph sinuses into the lymphoreticular cords and further into the AGC. The mobility of the macrophages is remarkably lower after phagocytosis of Candida cells.
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    URL: http://dx.doi.org/10.1007/BF00204887
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    Differentiation and transdifferentiation of adrenal chromaffin cells of the guinea pig (1983)
    Springer
    Cell & tissue research 229 (1983), S. 299-308 
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    ISSN: 1432-0878
    Keywords: Adrenal chromaffin cells ; Plasticity ; Transplants ; Kidney capsule ; Ultrastructure ; Catecholamine biochemistry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Histochemical, ultrastructural and biochemical studies (quantitative determinations of catecholamines (CA) and phenylethanolamine N-methyltransferase (PNMT) activity) were carried out on autologous transplants of adult guinea-pig adrenal medulla under the kidney capsule, in order to investigate the specific influences of a virtually nerve-free environment in comparison to those mediated by a densely innervated one such as in the iris (cf. Unsicker et al. 1981). Three weeks after transplantation chromaffin cells survived well, most cells maintaining their morphological identity in terms of adrenaline (A) storage, although biochemically measured A and PNMT had dramatically decreased. Chromaffin cells in transplants extended neurite-like processes in an identical fashion as seen in transplants to the anterior chamber of the eye and in culture. Chromaffin cells were frequently connected by synaptoid contacts, but did not receive cholinergic synapses as observed in transplants to the iris. It may be concluded that the growth factor(s) eliciting neurite outgrowth from transplanted chromaffin cells are rather ubiquitously present, independent of whether the transplantation site is sparsely or richly innervated.
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    Structural and functional studies of the adrenal zona glomerulosa in sodium-depleted and sodium-loaded sheep (1983)
    Springer
    Cell & tissue research 229 (1983), S. 515-531 
    Details
    ISSN: 1432-0878
    Keywords: Adrenal zona glomerulosa ; Ultrastructure ; Sodium depletion ; Sodium loading ; Sheep
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of alterations in sodium status upon the morphology of the adrenal zona glomerulosa in sheep have been examined qualitatively and quantitatively, using lightand electron microscopy, and correlated with functionally related biochemical data. With severe sodium depletion induced by parotid-cannula drainage, there was mitotic activity throughout the zona glomerulosa, and glandular cells showed striking ultrastructural changes. These changes particularly affected mitochondria, which were enlarged, rounded and showed replacement of their normal lamelliform cristae by thin elongated cristal elements and bundles of tubular “rod-like” structures. Quantitative morphometric studies showed an increase in the volumes of zona glomerulosa cells, nuclei, mitochondria, smooth and granular endoplasmic reticulum, and Golgi profiles. In contrast, with dietary sodium loading, zona glomerulosa cells appeared shrunken and showed cytoplasmic lipid accumulation; mitochondria and other organelles were not significantly altered. The correlation of the ultrastructural cytological alterations in zona glomerulosa cells in sodium-depleted sheep with raised blood aldosterone levels suggests that such morphologic changes reflect a heightened capacity of these cells for aldosterone biosynthesis and secretion. These changes may also account for the increased sensitivity of the zona glomerulosa to aldosterone-producing stimuli during sodium deficiency.
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    Variation in sperm morphology in the Australian rodent genus, Pseudomys (Muridae) (1983)
    Springer
    Cell & tissue research 229 (1983), S. 611-625 
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    ISSN: 1432-0878
    Keywords: Spermatozoa ; Ultrastructure ; Pseudomys (Muridae, Rodentia)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Sperm morphology among the various members of the genus Pseudomys showed great interspecific variation. In P. apodemoides, P. desertor, P. fumeus, P. gracilicaudatus, P. hermannsburgensis, P. higginsi and P. nanus the sperm head was bilaterally flattened and possessed three hooks, the length of which varied somewhat between species. The top hook contained nuclear, subacrosomal and acrosomal material, whereas the two lower ventral hooks displayed largely only an extension of the subacrosomal material. Four other species of Pseudomys had no ventral hooks in their sperm head. In P. novaehollandiae there was a single long top hook, whereas in P. pilligaensis it was almost nonexistent. Neither the sperm head of P. delicatulus, nor that of P. shortridgei possessed any hooks; the former became narrower towards the tip, whereas the latter was spatulate in shape. The acrosome covered about two thirds of the nucleus and varied considerably in shape between species. Insertion of the connecting piece of the tail occurred on the lower ventral side of the sperm head in all species with a long top hook but was nearly basal in P. delicatulus and midbasal in P. shortridgei. The ultrastructure of mid and principal pieces was similar among species, but the number of gyres of mitochondria ranged from about 64 to 100.
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    Ultrastructure of sensory receptors on the labium of the rice brown planthopper (1983)
    Springer
    Cell & tissue research 230 (1983), S. 353-366 
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    ISSN: 1432-0878
    Keywords: Homoptera ; Labium ; Sensilla ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The ultrastructure of the sensory receptors located on the labium of the rice brown planthopper is described; possible functions of individual receptors are suggested on morphological grounds. Uniporous chemosensilla which may or may not possess a mechanoreceptive dendrite, domed multiporous chemosensilla, and mechanoreceptive pegs are present on the flattened labial tip. Mechanoreceptive pegs are distributed over the labium. The fine structure of a multilobed sensillum located on either side of the labium is also described.
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    URL: http://dx.doi.org/10.1007/BF00213809
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    Effects of melatonin on synaptic ribbons in pinealocytes of the Chinese hamster, Cricetulus griseus (1983)
    Springer
    Cell & tissue research 233 (1983), S. 59-67 
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    ISSN: 1432-0878
    Keywords: Pineal gland ; Synaptic ribbon ; Melatonin ; Ultrastructure ; Chinese hamster (Cricetulus griseus)
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The effects of melatonin on synaptic ribbons (SR) in pinealocytes of the Chinese hamster (Cricetulus griseus) were examined. SR were classified into types 1, 2 and 3, which appear as rods, round or irregular bodies and ring-shaped structures, respectively; a synaptic ribbon index (SR index) was determined for the three types. Administration of two doses of 1.5 mg/kg melatonin at noon and 3 p.m. causes an increase in the type-1 and type-2 SR indices 3 h after the second injection in hamsters kept under alternating light and dark conditions (lights on from 7 a.m. to 7 p.m.). Likewise, in animals that are exposed to extended light for 6 h and receive two doses of melatonin at 7 p.m. and 10 p.m., an increase in the type-1 and type-2 SR indices occurs 3 h after the second injection. The increase in the type-2 SR index induced by melatonin administration to hamsters exposed to extended light is greater than the increase in the type-1 SR index under the same experimental conditions. Type-2 SR index, but not type-1 SR index, increases following bilateral superior cervical ganglionectomy. An increase in type-1 and type-2 SR indices occurs at 6 p.m. in ganglionectomized animals administered two doses of melatonin 6 h (noon) and 3 h (3 p.m.) before the time of sacrifice. No significant change is observed in type-3 SR index in animals subjected to any of the above treatments. The results indicate that exogenous melatonin may act directly on pinealocytes of the Chinese hamster to cause an increase in size and/or number of the type-1 and type-2 SR. Type 3-SR may have a role different from that of type-1 and type-2 SR; type-1 and type-2 SR may be functionally related.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222232
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  • 93
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    A peculiar myofibrillar pattern in the murine muscletendon junction (1983)
    Springer
    Cell & tissue research 233 (1983), S. 227-231 
    Details
    ISSN: 1432-0878
    Keywords: Muscle-tendon junction ; Ultrastructure ; Myofibrillar pattern ; M. flexor digitorum longus ; Mouse
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The muscle-tendon junctions of adult mice show a special arrangement of myofibrils. Essentially, the myofibrils are oriented in an anchor-like manner in the large finger-shaped processes of the muscle fiber, which contain “mitochondrial sacks” (Demmel et al. 1979) in a subsarcolemmal position. Furthermore, the single myofibril frequently branches out into smaller fibrils. It is suggested that due to the three-dimensional arrangement, these processes gain a high rigidity during contraction, thus maintaining their shape and preserving the “mitochondrial sacks”.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00222246
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  • 94
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    Spermiogenesis in the rainbow trout (Salmo gairdneri) (1983)
    Springer
    Cell & tissue research 233 (1983), S. 265-284 
    Details
    ISSN: 1432-0878
    Keywords: Spermiogenesis ; Rainbow trout ; Ultrastructure ; Spermatids ; Chromatin
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In an ultrastructural study on the spermiogenesis of the rainbow trout (Salmo gairdneri R.) four spermatogenetic stages were identified. In young round spermatids, the nuclear chromatin was first heterogeneous (euchromatin and heterochromatin). Subsequently, it became more homogeneous and started to condense in the form of coarse granules and fibers and then into fibrils associated in ribbon-like elements which eventually partly fused together. During early spermiogenesis, a juxtanuclear vacuole appeared in the area where the nuclear envelope was specialized due to condensation of material between the two envelopes and a slight accumulation of nuclear material. This area was finally located in the anterior part of spermatids and spermatozoa; it probably plays a role during fertilization. A flagellar rootlet appeared early in spermiogenesis; it may play a role in the attachment of the flagellum to the nucleus since it persisted until the centriolar complex was definitively fixed in the implantation fossa. The flagellum did not display a plasma membrane and was first located in the cytoplasm, but when it was later extruded from the cell, it acquired a membrane. The cytoplasm was rich in ribosomes (free or in small groups) but poor in membranous organelles. The few mitochondria polarized around the centriolar complex were finally organized into an annular mid-piece. The spermatids remained connected by intercellular bridges until the end of spermiogenesis. The complexity of trout spermiogenesis is intermediate between that in poecilids and that in carp and pike, which have very simple spermatozoa. The role of the material from the nucleus and the cytoplasm reaching the Sertoli cell in the control of spermatogenesis has been discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00238295
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  • 95
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    Erythropoiesis in the thymus of the spotless starling, Sturnus unicolor (1983)
    Springer
    Cell & tissue research 232 (1983), S. 445-455 
    Details
    ISSN: 1432-0878
    Keywords: Avian thymus ; Intrathymic erythropoiesis ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary Although previously described in other avian species, intrathymic erythropoiesis is a remarkable feature of the thymus of Sturnus unicolor. In discrete stages of the life cycle of this species, erythroblasts and mature erythrocytes occupy large areas of the thymic cortex and cortico-medullary border. Simultaneously, degenerated thymocytes and epithelial-reticular cells occur in the same areas. The relationship between intrathymic erythropoiesis, degeneration of cortical lymphocytes and epithelial-reticular cells, and macrophage activity is discussed and related to a possible functional role of sex hormones in this phenomenon.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00213799
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  • 96
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    Ultrastructural and functional development of macrophages in the dermal tissue of rat fetuses (1983)
    Springer
    Cell & tissue research 232 (1983), S. 539-552 
    Details
    ISSN: 1432-0878
    Keywords: Fetal macrophages ; Subepidermal mesenchyme (dermal tissue) ; Rat fetus ; Ontogeny ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary After about 12 days of gestation, fetal macrophages begin to appear in the subepidermal mesenchyme of rat fetuses. The macrophages are ultrastructurally characterized by cytoplasmic vacuoles, abundant polyribosomes and long filopodia. Immunocytologically, they possess Fc and complement (C3) receptors on the cell surface and are capable of immune phagocytosis, Latex or carbon phagocytosis, and glass adherence. From 15 days of gestation, lysosomal granules and miropinocytic vesicles gradually develop, together with an enlargement of Golgi complexes, whereas the number of polysomes and the number and size of cytoplasmic vacuoles are gradually reduced when gestation ends. Finally, the macrophages become amoeboid. Non-specific esterase and endogenous peroxidase activities are always absent in these macrophages. In culture experiments with cell suspensions prepared from the mesenchyme, fetal macrophages show a similar maturation process. Autoradiography with 3H-thymidine demonstrates a high proliferative capacity of the macrophages, particularly during the fetal stage.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216427
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  • 97
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    The in vitro development of the pupal integument and the effects of ecdysteroids in Tenebrio molitor (Insecta, Coleoptera) (1983)
    Springer
    Cell & tissue research 232 (1983), S. 493-511 
    Details
    ISSN: 1432-0878
    Keywords: Ecdysteroids ; Epidermis ; In vitro differentiation ; Tenebrio ; Ultrastructure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary In order to study the pupal-adult metamorphosis of Tenebrio in vitro, pupal sternites of different ages were cultured in Landureau's medium and their development systematically observed by electron microscopy. In hormone-free medium, explants taken from young pupae do not secrete pupal postecdysial cuticle in vitro, and the epidermis spontaneously detaches from the pupal cuticle. On the contrary, explants taken from pharate adults continue to secrete adult preecdysial cuticle in vitro, and the epidermis never detaches from the cuticle. Ecdysterone in physiological concentrations (0.2 to 4 μg/ml) induces the secretion of a new cuticle in explants from young pupae but the epidermis remains undifferentiated. Ecdysone is necessary for the induction of some adult differentiation. Moreover, the quality of the cuticle secreted in vitro is increased by the addition of 2% foetal calf serum; the best results have thus far been obtained in a medium containing 0.2 μg/ml ecdysone, 1 μg/ml ecdysterone, and 2% foetal calf serum.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216424
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  • 98
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    Electron-microscopical study of the operculum in anuran tadpole after extirpation of the right forelimb during metamorphosis (1983)
    Springer
    Cell & tissue research 232 (1983), S. 513-527 
    Details
    ISSN: 1432-0878
    Keywords: Skin ; Operculum ; Fenestration ; Ultrastructure ; Anura ; Metamorphosis
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The process of histolysis and fenestration of the skin of the prospective opercular perforation region of Rana japonica after extirpation of the right forelimb was observed during metamorphosis by transmission and scanning electron microscopy. Epidermal cells of the belly of the tadpole, including the operculum, are extremely similar in their ultrastructure. Epidermal cells of the prospective opercular perforation region during metamorphosis become thin and vacuolated especially around the nucleus perhaps by autolysis, associated with lysosomal activity. The histolysis and formation of the perforation of the operculum occurs in the complete absence of forelimb. Macrophages containing phagosomes and lymphocytes or other blood cells are almost always found in the intercellular epidermis. Necrotic epidermal cells progressively separate by cleft formation and slough off without cornification.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216425
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  • 99
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    Ultrastructure of the reactivated corpus luteum after embryonic diapause in the marsupial, Macropus rufogriseus banksianus (1983)
    Springer
    Cell & tissue research 228 (1983), S. 61-74 
    Details
    ISSN: 1432-0878
    Keywords: Marsupial ; Ultrastructure ; Corpus luteum ; Granules
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary During embryonic diapause in the red-necked wallaby, M. r. banksianus, both the corpus luteum and uterine blastocyst remain dormant, and are reactivated following removal of the suckling pouch young (RPY). The morphology of dormant and reactivated corpora lutea has been studied throughout the 26.5 days of delayed gestation. Corpora lutea at 0, 2 1/2, 4, 9, 14, 21 and 25 days after RPY were fixed by perfusion. From day 4 to day 14 after RPY there was a progressive increase in the amount of smooth endoplasmic reticulum and the numbers of mitochondria. However there was a decrease in mitochondrial size from 1–2 μm in diameter (0 days after RPY) to 0.5–1 μm (14 days after RPY). Densely-staining granules (approximately 0.2 μm in diameter) were first observed in the luteal cells at 4 days after RPY. The maximum density of granules was observed at 21 days after RPY. Shortly before birth (25 days after RPY) the number of secretory granules had significantly decreased and the features of cellular regression were evident. As with the eutherian mammals, the wallaby luteal cells have all the structural organelles associated with steroid hormone production. The numbers of densely-staining granules are greatest at 21 days after RPY and may reflect the luteal progesterone content since similar granules in the sheep and cow have been shown to be associated with elevated levels of progesterone.
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    URL: http://dx.doi.org/10.1007/BF00206265
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  • 100
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    Glomerular ultrastructure of the trout, Salmo gairdneri (1983)
    Springer
    Cell & tissue research 230 (1983), S. 205-218 
    Details
    ISSN: 1432-0878
    Keywords: Kidney ; Glomerulus ; Ultrastructure ; Teleosts ; Seawater adaptation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Summary The epithelial ultrastructure of the glomerulus of fresh- and sea-water adapted rainbow trout, Salmo gairdneri was examined by scanning and transmission electron microscopy after in vivo-perfusion fixation. Adaptation to seawater for a period of up to 9 weeks was not associated with a change in glomerular size, although after one year in seawater both glomeruli and their capsules were significantly smaller than the glomeruli of freshwater adapted fish. In freshwater adapted trout the epithelial ultrastructure conformed to the general vertebrate pattern, with rounded podocytes, well-defined primary processes and interdigitating pedicels. Adaptation to seawater was associated with a marked increase in the frequency of cytoplasmic microprojections. In many glomeruli there was a flattening of the podocytes, broadening of the primary processes, and areas of closely-packed pedicels were common. These observations are discussed in the light of previous studies on the mammalian kidney and the changes of single nephron function known to be associated with adaptation of trout to increased environmental salinities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00216040
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