Showing papers by "Free University of Berlin published in 1969"

Micropuncture and Microanalysis in Kidney Physiology

Abstract: Micropuncture techniques and microanalysis have been the prerequisites for the investigation of two major questions in kidney physiology: 1 At what sites along the nephron are the different substances transported into or out of the tubular urine; 2 How do these transport mechanisms work, eg by what forces and through which mediating structures are substances moved from one compartement into another and how are these processes regulated

An electron microscopic study of meningiomas.

Abstract: Seventeen surgically removed meningiomas of the endotheliomatous and five of the fibromatous type were investigated with an electron microscope. Differences of the development of cytoplasmic processes and the relations between plasma membranes of blastomatous cells were observed in endotheliomatous meningiomas. In four of the fibromatous tumors the cell groups were surrounded by spaces of connective tissue. Although most of the tumor cells were light cells and are not essentially different from the tumor cells of the endotheliomatous meningiomas, the histological structure of fibromatous meningiomas is clearly distinguished from the endotheliomatous type, because of the greater amount of connective tissue. The dark cells may be divided into two types: the first was found in those four tumors, where the connective tissue is well developed, while the second one only occurred in one of the tumors. The analysis of the inner cell structure as well as the presence of interstages between dark and light cells makes it probable that dark and light cells are different types of one original cell. The cause of this different appearance of the menigioma cells is discussed. The fine structure of the tumor cells showed a great similarity with that of normal arachnoidal cells. Conclusions on the blastodermic origin of normal and blastomatous meningial cells on the basis of ultrastructural characteristics, however, seem to be premature.

Studies on the functional significance of efferent innervation in the auditory system: afferent neuronal activity as influenced by contralaterally applied sound.

Abstract: Recordings were made using stereotaxic techniques from single neurons of the cochlear nucleus of cats in very light barbiturate anesthesia (supplemented by local anesthesia). The responses of afferent neurons to ipsilateral acoustic stimulation were recorded and compared with the responses following binaural stimulation. The sound pressure levels in both ears were kept low enough to avoid interaural cross-talk. It was shown that contralateral stimulation reduced the response of an afferent neuron to ipsilateral stimulation. This inhibition was dependent, on the frequency of the sound presented to the contralateral ear. Adjacent frequencies inhibited more strongly than the characteristic frequency itself or more widely removed frequencies. The dependency of the inhibition on frequency took the form of a W-shaped curve. From this frequency dependent behavior it is concluded that this inhibition leads to an increase of pitch discrimination. This effect can only be explained as resulting from the efferent innervation.

Semantic Determinants of Pauses

Abstract: The following experiment presents evidence that variations in semantic context can produce changes in the rate and length of pauses in a situation in which syntactic and other variations are minimized. Each of 40 Ss read two paragraphs aloud and after each paragraph retold the “story” without further instructions. Each paragraph consisted of five sentences, each containing 23 syllables. The third sentence was either in accord with the story or an unusual occurrence (depending on exchange of subject and object). The most important experimental finding was that both number and length of unfilled pauses are more frequent throughout the unusual stories as compared with the usual ones. In the readings, the effect was limited to the critical sentence and the pauses immediately thereafter. The evidence supports the view of the authors that the role of semantic context has been underestimated in psycholiguistic research to date.

Urodelen-atlas aus dem obersten Bajocien von SE-Aveyron (Südfrankreich)

Abstract: Durch Anwendung von Aufbereitungs- und Konzentrationsverfahren an einem bituminosen Mergel des Ober-Bajocien im Dept. Aveyron, Sudfrankreich, wurde eine Fauna isolierter Fisch- und Tetrapodenreste gewonnen.

Activity and isolated phytoestrogen of shrub palmetto fruits (Serenoa repens small), a new estrogenic plant

Abstract: 21 Tage alten weiblichen Mausen wurde wahrend dreier Tage durch s.c. Injektionen ein Extrakt von Sabalfruchten (Serenoa repens Small, fruher Sabal serrulatum Schult) verabreicht. Es wurde eine hohe ostrogenaktivitat festgestellt, welche durchβ-Sitosterol hervorgerufen wird, welches in dieser Pflanze in relativ hoher Konzentration vorhanden ist.

Zur wirkung von Miracil auf menschliche Leukozytenchromosomen in vitro

Abstract: In human leukocyte chromosomes in vitro the thioxanthon derivative 1-(2-diethylaminoethylamino)-4-methylthioxanthone hydrochloride (Miracil D) induces especially achromatic lesions (AL) und chromatid breaks (B′). The frequencies of isochromatid breaks (B″) are at the control level, and chromatid translocations (RB′) are only found at the two highest concentrations tested. The results are compared with the findings of Luers (1955) on the mutagenic action of the same substance in Drosophila and with the action of the monofunctional ethyleneimino compound 2-ethyleneimino-5.6.7.8.-tetrahydronaphtoquinone-1,4 (A 137) in Drosophila and human leukocyte chromosomes in vitro. A connection of AL with mutational events seems doubtful.

Polyvinylsulfate: Interaction with Complexes of Morphogenetic Factors and Their Natural Inhibitors

Abstract: The inactivation of the mesodermalizing inducing factor by its natural inhibitor is completely abolished by low concentrations of polyvinylsulfate.

Time course of development of transtubular sodium concentration differences in proximal surface tubules of the rat kidney. Micropuncture experiments in intact and adrenalectomized rats.

Abstract: Int the proximal and distal surface tubules isotonic Na reabsorption (Φ Naout) is impaired by adrenalectomy. In the present experiments the time course of development of transtubular Na concentration differences (Na)P−(Na)TF was studied in the proximal convolution. 1. Na concentration was measured in free flow mannitol diuresis. Endproximal (Na)P−(Na)TF averaged 23.0±0.5 meq/l after 8.5±0.6 sec (controls) and 15.2±1.7 meq/l after 13.6±0.5 sec (adrenalectomized rats). 2. In modified stopped flow experiments tubular fluid, aspirated at the beginning of the proximal convolution in mannitol diuresis, was injected between two oil columnes and reaspirated after 28–36 sec of contact time. (Na)P−(Na)TF was 30.1±1.4 meq/l and 24.7±2.5 meq/l in the controls and adrenalectomized rats respectively. 3. (Na)P−(Na)TF in steady state (i. e. after 60 sec of contact time) were 33.6±0.8 meq/l and 41.8±1.2 meq/l in the 2 groups. From the results we derive at the conclusion that in adrenal insufficiency proximal sodium reabsorption is not only affected by an impairment of the intrinsic transport capacity but also by a proportional decrease of leak permeability for sodium. 4. Due to an increased transit time in adrenal insufficiency fractional reabsorption of sodium and of potassium was unchanged in the proximal convolution. Therefore it seems likely that the same compensation mechanism as for sodium holds for potassium and the reabsorption of potassium is impaired in adrenal insufficiency also in the proximal convolution.

Optical investigation of DyFeO 3

Abstract: Optical absorption spectra of DyFeO3 have been investigated at 1.2≦T≦4.2 °K, andT=77 °K From the temperature dependent lineshift a Neel temperature ofTN=(3.8±0.5) °K is deduced for the dysprosium sublattices. The groundstate splitting due to the iron-dysprosium interactions is about 1.5 cm−1 and due to the dysprosiumdysprosium interactions (5.0±1.4) cm−1. Zeeman studies give the magnetic moment of the dysprosium ions asμ=(9.2±1.0)μB.

Reworked dolomite crusts in the wettersteinkalk (ladinian, alpine triassic) as indicators of early supratidal dolomitization and lithification

Abstract: SUMMARY Dolomitic intraclastic sediments intercalated in a cyclic limestone-dolostone sequence of the Wettersteinkalk represent a rock type with reworking fabrics demonstrating early lithification and dolomitization. The extreme flatness and the angularity of the pebble-sized doloclasts, the lack in plastically deformed dolomitic fragments, and clasts of previously cementated arenites and oncolites testify to a pre-reworking consolidation which, besides biogenic stabilization and dehydration, requires an early cementation. In the different types of doloclasts cementation both by dolomite and by calcite has been confirmed by stained peels and thin-sections, electron-microphotographs, and electron-microprobe analysis. The prevailing rock type, a very poorly sorted mixture of doloclasts and minor amounts of rounded limeclasts with a pelletal calcite mud matrix is interpreted as storm sediment formed by the introduction of subtidal lime muds to dolomite incrusted supratidal flats.

Optical investigation of HoFeO 3

Abstract: The absorption spectra of HoFeO3 were investigated in the near infrared spectral region at temperatures of 1.2, 4.2, 20 and 77 °K respectively. At every temperatureT≦20 °K all the absorption lines show the same splitting which is attributed to the groundstate; this splitting is (7.2±0.5) cm−1 at 20 °K and decreases to (4.9±0.8) cm−1 extrapolated to 0 °K. From these splittings the holmium-iron and the holmiumholmium interactions can be deduced.

Lung scanning as a screening method for cancer of the lung

Abstract: After injection of 131I‐MAA (macro‐aggregated human serum albumin), the authors obtained pulmonary scans from 500 patients with various pulmonary diseases. The results of scanning and of standard roentgenographic examination are compared on the basis of 138 cases with definitely diagnosed malignant pulmonary tumors. In all cases with central tumors;, i.e., tumors that were located near the hilus, the scan was abnormal and thus indicated a disorder of pulmonary perfusion. In contrast to this, radiologic examination (thoracic films in two planes and, if indicated, fluoroscopy) only disclosed direct or indirect signs of cancer in 88% of these cases. Therefore, lung scanning as a screening method for central pulmonary tumors is a more sensitive diagnostic tool than standard roentgenographic examination. In cases of peripheral pulmonary tumors, a perfusion disorder which is larger than the radiologically recognizable lesion indicates central metastases.

Hyperfine fields on Hafnium nuclei in iron and gadolinium metal

Abstract: The recoil implanation perturbed angular correlation technique, IMPACT, has been used to study the hyperfine interaction in180Hf in iron and gadolinium. The perturbed angular correlation through the Coulomb excited 4+ state was used, thus minimizing the effect of quadrupole interactions. The effective hyperfine fields on Hf in iron and gadolinium are determined to have the same sign,negative, and magnitudes of (507±60) kOe and (304±31) kOe, respectively. Results are compared with values reported from several other experiments ostensibly measuring the same quantity. Problems inherent in the various experimental techniques are considered.

Reflections in bounded symmetric domains

Abstract: © Scuola Normale Superiore, Pisa, 1972, tous droits réservés. L’accès aux archives de la revue « Annali della Scuola Normale Superiore di Pisa, Classe di Scienze » (http://www.sns.it/it/edizioni/riviste/annaliscienze/) implique l’accord avec les conditions générales d’utilisation (http://www.numdam.org/conditions). Toute utilisation commerciale ou impression systématique est constitutive d’une infraction pénale. Toute copie ou impression de ce fichier doit contenir la présente mention de copyright.

Letter to the Editor-Computational Experience with a Zero-One Programming Problem

Abstract: Previous papers by Fleischmann and by Lemke and Spielberg have reported computational experience with different algorithms for zero-one programming problems. This note supplements these papers by describing the experience with a special zero-one programming problem that arose from a mining context.

An impregnation technique for studying distribution of mitochondria in central nervous system.

Abstract: An impregnation technique for demonstration of mitochondria in central nervous system has been described. Formol perfused material is being chromated, embedded in paraffin and impregnated with a modified Nauta's method. The reaction is specific since reduced silver particles are deposed within the matrix of mitochondria. Phenomenon of complete and incomplete impregnation is discussed. Mitochondria in perikarya of neurons, dendrites and glia tend to be unstained if the impregnation is incomplete, while axonic and praesynaptic ones are labelled. In neuropil of different regions of the brain various types of mitochondrial aggregates appear in complete impregnation. The method may be a valuable tool for studying brain architecture and synaptology.

Zur Struktur und Funktion des Exkretionssystems von Ascaris lumbricoides L.

Abstract: Das Exkretionssystem von Ascaris lumbricoides besteht aus einer einzigen grosen etwa H-formigen Zelle, deren lange Sehenkel in den lateralen Epidermisleisten der Tiere liegen. Die Schenkel sind jeweils von einem intrazellularen Kanal durchzogen, dessen Lumen nach den elektronenmikroskopischen Untersuchungen nach hinten zu schnell abnimmt. Die Kanalwandung ist aus geschichteten Cytoplasmaplatten aufgebaut, die anscheinend aus einer dicht gepackten Vesikelschicht hervorgehen. Auch die ausere Zellmembran besitzt Oberflachendifferenzierungen in Form tiefer Einfaltungen. Die Zellschenkel sind von schwammartigen Hullzellen zur Leibeshohle hin umgeben. Eine Basalmembran bildet die Grenze zur Leibeshohle.

Correlation between poliomyelitisvirus-reproduction-cycle, chromosomal alterations and lysosomal enzymes.

Abstract: Complete poliovirus reproduction-cycle in human aneuploid tissue culture cells causes chromosomal damage and increase of non-particulate lysosomal enzymes. — Guanidine-inhibition of late stages of infection gives evidence that breakage and c-anaphase-like chromosomes are independent of the complete reproduction-cycle. Severe diffuse chromoomal alterations, however, and increase of lysosomal enzymes require late stages of infection. — In this host-virus-system lysosomal enzymes are not responsible for incidence of chromosomal breakage and c-anaphaselike figures. The role of lysosomal enzymes for severe diffuse chromosomal alterations is still in question.

Das Blutvolumen in den verschiedenen Stadien der tierexperimentellen renovasculären Hypertonie

Abstract: Bisher wurde nur in vereinzelten Fallen uber Blutvolumenbestimmungen bei der renovascularen Hypertonie berichtet. Slaton u. Biglieri [1] fanden bei sechs Patienten mit Nierenarterienstenose und sekundarem Aldosteronismus, bei denen der Bluthochdruck durch eine spatere Operation beseitigt werden konnte, eine deutliche Abnahme des Blutvolumens. Den gleichen Befund erhoben Frohlich u. Mitarb. [2] bei 15 Hochdruckkranken mit ein- und beidseitiger Nierenarterienstenose infolge fibromuskularer Hyperplasie. Im Gegensatz hierzu wurde von Ledingham u. Cohen [3].wahrend der.Entwicklung.der tierexperimentellen enovascularen Hypertonie eine vorubergehende Vergroserung des Plasmavolumens nachgewiesen. Die Untersucher bestimmten das Plasmavolumen mit Evansblue bei Ratten, deren Bluthochdruck durch eine einseitige Nierenarterienstenose und kontralaterale Nephrektomie erzeugt wurde. Von den gleichen Autoren [4] wurde bei akuter Ruckbildung der tierexperimentellen renovascularen Hypertonie eine Abnahme des Plasmavolumens bei gleichbleibendem Erythrocytenvolumen beobachtet. Die Abnahme des Blutvolumens wurde durch eine gesteigerte Diurese nach Entfernung des Nierenarterienklipps erklart.

Zur Anwendung hoher Furosemiddosen bei akutem Nierenversagen

Abstract: Die protektive Wirkung von Mannitol bei drohendem akutem Nierenversagen [1, 2, 3, 4, 9, 12) ist hinreichend bekannt und wird in Form des sog. „Mannitol-Testes “ auch in differentialdiagnostischer Hinsicht ausgenutzt [5, 14]. In Anbetracht der Tatsache, das Mannitolinfusionen nicht in allen Fallen in der Lage sind [8, 14], die Auspragung eines akuten Nierenversagens zu verhindern, schien es von Interesse, die zusatzliche Wirkung hoher Furosemiddosen zu prufen.