Showing papers by "University of Zurich published in 1972"

Innervation Densities of the Cochlea

Abstract: In normal cats the nerve fibres have been counted at different levels from the spiral ganglion to the outer hair cells by means of light and electron microscopy. The relative numbers were calculated per millimeter cochlear length. Thus more exact information has been obtained about the ratio of the nerve supply to the inner and outer hair cells, the innervation density and the fibre branching in different cochlear turns. The great predominance of the innervation of the inner hair cells is confirmed. Only a small proportion of all nerve fibres leads to the outer hair cells. There is an overall innervation density maximum in the upper basal turn. About 95% of the afferent cochlear neurons are associated with the inner hair cells and only about 5% with the outer hair cells. The neurons associated with the outer hair cells have entirely different structural characteristics and do not undergo retrograde degeneration.

The fine structure of freeze-fractured presynaptic membranes

Abstract: Electron micrographs of presynaptic membrane faces were obtained from replicas of aldehyde-fixed, freeze-fractured neuropil of mammalian and avian C.N.S. There is strong evidence that the presynaptic membrane is split and that the exposed membrane faces represent the inner and outer membrane leaflet respectively. Presynaptic sites on the inner face appear as patches adhering to postsynaptic elements and include a distinctly indented area. They bear clusters of membrane particles and a varying number of small protuberances. The latter apparently occur in presynaptic membranes exclusively and form hexagonal patterns corresponding to the ‘presynaptic vesicular grid’. Evidence is presented that the protuberances are temporary attachment sites of transmitter vesicles to the presynaptic membrane. These contacts may be identical with the sites of transmitter release.

Reconstitution of Qβ Replicase Lacking Subunit α with Protein-Synthesis-Interference Factor i

Abstract: We have isolated a form of Qβ replicase lacking subunit α and shown that it is deficient in the utilization of Qβ-plus strand RNA as template but competent to utilize Qβ-minus strands, poly(C) and “6-S” RNA. The functional identity of subunit α and protein-synthesis-inhibition factor i was proven by their equivalent capacity to restore full Qβ RNA-directed activity of α-less replicase.

Steroid 17, 20‐desmolase deficiency: a new cause of male pseudohermaphroditism

Abstract: SUMMARY In a child with male pseudohermaphroditism (ambiguous external genitalia, XY sex chromosomal constitution and normal adrenocortical function), incubations of testicular tissue with pregnenolone/progesterone, 17α-hydroxy-pregnenolone/17α-hydroxyprogesterone and androstenedione/dehydroepiandrosterone showed that testosterone could be formed from androstenedione and dehydroepiandrosterone only, but not from other substrates. In urine, testosterone did not increase after HCG, but small amounts of pregnanetriolone were found, which increased after HCG and ACTH. There was no DHA increment after ACTH. It is concluded that this patient, as well as a first cousin and a gonadectomized maternal 'aunt' with the same clinical and urinary steroid findings have testicular and adrenal steroid 17,20-desmolase deficiency, causing a defect of androgen biosynthesis, which has not previously been described. The heredity of this condition seems to be autosomal or X-chromosomal.

Die Reaktion des Knochens auf Knochenzement bei der Allo-Arthroplastik der Hüfte

Abstract: Es wird uber das Verhalten des knochernen Lagers nach Implantation von autopolymerisierendem Methylmethacrylat (Knochenzement) berichtet. Der Untersuchung liegen die makroskopischen und mikroskopischen Befunde vom proximalen Femurende und von der Huftpfanne zugrunde, die an 23 Fallen von Gelenkersatz durch Huftkopfendoprothesen oder Huftgelenktotalendoprothesen erhoben wurden. Das Material stammt aus Autopsien und Biopsien des Pathologischen Instituts der Universitat Zurich und aus der Orthopadischen Universitatsklinik Frankfurt am Main. Der Knochenzement verankert sich an Unregelmasigkeiten des knochernen Lagers; die Verankerung ist deshalb am besten im spongiosen Knochen der proximalen Femurmetaphyse. Die Implantation des selbsthartenden Kunststoffes verursacht durch Gefaszerstorung, Warmeentwicklung unter der Polymerisation oder durch Monomerabgabe Nekrosen am Lagergewebe (Initialphase). Die Revitalisierung erfolgt am Knochenmark nach Beseitigung des Fettes durch bindegewebige Organisation, am Knochen durch schleichenden Umbau; diese Vorgange fuhren zur „Einheilung“ des Implantates (Reparationsphase). Spatestens nach 2 Jahren ist die Organisation der Nekrosen abgeschlossen (Stabilisationsphase). In den Markraumen hat sich dann wieder regelrechtes Knochenmark angesiedelt, das durch eine Bindegewebsmembran gegen den Zement hin abgedeckt wird. Die nekrotischen Knochenanker sind abgebaut und mehr oder weniger vollstandig durch neuen Knochen ersetzt worden. Das knocherne Lager erfahrt insgesamt eine Umstrukturierung, die sich in einer Glattung der Kontaktflache zum Zement und in Osteoporose des ubrigen Knochens ausert. Extensiver Knochenumbau kann eine Lockerung des Implantates begunstigen. Die Bindegewebsmembran absorbiert Mikrobewegungen zwischen Implantat und Lager. Oberflachliche Fibrinexsudationen und Blutungen stellen sich durch Verletzungen des Gewebes bei starkeren Verschiebungen ein und sind ebenfalls als Vorboten einer Lockerung des Implantates anzusehen. Die Gewebskonturen an der Grenze zum Zement sind glatt oder gitterartig. Stets sind hier vielkernige Fremdkorperriesenzellen vorhanden, die mit zunehmender Verweildauer des Implantates an Zahl zunehmen. Die Moglichkeit, das Fremdkorperriesenzellen in der Lage sind, den Zement anzugreifen, kann nicht ausgeschlossen werden. Als Schlusfolgerungen fur die Klinik ergeben sich aus unseren Untersuchungen die Forderungen nach moglichst optimaler Verankerung des Zementes bereits bei der Implantation, nach Vermeidung von Schadigungen des Implantatlagers, nach Verhutung einer Uberlastung der Verankerung im Knochen sowie nach Beachtung einer sorgfaltigen Indikationsstellung.

Methodik der Kapillar-Gas-Chromatographie Hinweise zur vollen Ausnützung hochwertiger Säulen

Abstract: Der vorliegende II. Teil bezweckt, die wichtigsten Zusatzinformationen zu vermitteln, welche einen erfahrenen Benutzer gepackter GC-Saulen in die Lage versetzen, Kapillarsaulen hoher Qualitat uber langere Zeit hinweg zu hoher Leistung zu bringen. Diese Informationen betreffen ausschlieslich Glaskapillarsaulen, da sich deren Leistungen in mehrfacher Hinsicht weit uber jene von Kapillaren aus Metall oder anderen Werkstoffen steigern lassen. Praktische Anleitungen zur Vorbereitung, zum Einbau in den Gas-Chromatographen, und zum Betrieb von Glaskapillarsaulen werden gegeben. Viel Raum wird der grosen Zahl haufig auftretender und zum Teil einschneidender Storungen-welche bei gepackten Saulen meist belanglos sind-sowie ihrer Feststellung und Behebung gewidmet. Die Sammlung solcher, aus der Arbeit mit gepackten Saulen nicht direkt ableitbarer Erfahrungen soll zeigen, welche Randbedingungen zum analytischen Erfolg entscheidend beitragen. Sie soll damit der verbreiteten Tendenz entgegenwirken, bei einem Miserfolg die Ursache zuerst bei der Kapillarsaule zu suchen.

Electron microscopic studies on the trabecular meshwork in glaucoma simplex

Abstract: In 20 cases of chronic simple glaucoma with cataract a trabeculectomy was carried out and the bioptic specimens were studied by electron microscopy. For the purpose of comparison similar specimens obtained from 14 cases of secondary glaucoma and 7 control eyes were investigated by the same methods. In many cases of glaucoma simplex deposits of homogeneous osmiophilic material (plaques) were found between the cell layers of the cribriform area of the trabecular meshwork adjacent to the inner wall of Schlemm's canal. These were not present to such an extent within the control specimens. The plaques differ in structure and size, and appear first in foci. In advanced stages of the glaucomatous disease, the entire juxtacanalicular region is filled with osmiophilic plaques of this kind. The nature of these substances is unknown.

The Larval Development of Imaginal Disks

Abstract: The life of holometabolous insects, such as Drosophila, is characterized by two separate and completely different phases of development. Out of the egg hatches a larva which then becomes transformed during metamorphosis into the adult insect, the imago. The future adult is “hidden” within the larva in the form of the so-called imaginal cells. After fertilization a series of syncytial divisions produces a homogeneous population of nuclei (energids) which later move into the cortical periplasm at the egg’s periphery where they form the cellular blastoderm (review by Anderson, 1972). This is probably the stage at which the presumptive imaginal cells are segregated from the larval cells (seep. 8). These two distinct populations of cells perform their specific vital functions at entirely different periods of development. During metamorphosis, the larval organization breaks down, and the adult insect is formed anew from the imaginal cells. (There are a few exceptional organ systems, e.g. the Malpighian tubules, that persist through metamorphosis.)

Dorsoventral asymmetry in the visual field of the bee,Apis mellifica

Abstract: 1. Bees can be trained to a special orientation αtr of a black-and-white disk (one half black, the other half white; angular diameter 130 °), offered on a vertical screen. Different test inclinations αt of the contrast line between the black and white area of the disk are discriminated from αtr (direction sensitivity curve, Figs. 3 and 4). 2. Insertions of contrasting sectors into the black and white area of the training pattern diminish the reaction frequency to that pattern (W- and B-functions, Figs. 6 and 7). Therefore the direction sensitivity curve can be approximately calculated by means of the B- and W-functions, because a rotation of the black-and-white disk is accompanied by the insertion of a white sector in the previously black area and vice versa (Fig. 5). 3. The effect of inserting contrasting areas in the black-and-white disk is the stronger, the more these insertions are located in the medial lower part of the visual field (Fig. 9, Tables 3 and 4). 4. The results provide strong evidence for the conclusion that the different positions of the visual field are topographically represented in the central nervous system of the bee, and that the middle lower part of the frontal visual field is most decisive for pattern recognition. They do not agree with the classical theory of form perception in insects, which is based on an integration of the stimuli effects all over the visual field, irrespective of their position within the visual field.

Lymphocyte-fibroblast interaction in the pathogenesis of inflammatory gingival disease.

Abstract: Eine morphometrische Analyse menschlicher, entzundeter Gingiva ergab im Vergleich zu normalem Bindegewebe 70% weniger Kollagenfasern, dreifach vergrosserte und pathologisch veranderte Fibroblasten und eine kleine Population charakteristischer Immunoblasten mit einer Zellansammlung, die zu 76% aus Zellen der Lymphozytenserie bestand. Die Grosse der Fibroblasten war positiv mit der steigenden Zahl der Lymphozyten korreliert. Diese Befunde weisen auf eine Immunreaktion mit zytotoxischen Auswirkungen auf Fibroblasten des gingivalen Bindegewebes hin.

Purification and Properties of an α-(1 → 3) Glucanohydrolase from Trichoderma harzianum

Abstract: As matrix compounds of dental plaque, extracellular polysaccharides of streptococcal origin seem to play an important role in the etiology of dental caries.'-5 These polysaccharides are not homogenous, either from a chemical or from a morphological point of view. Differences in water solubility are most apparent.6 Premature chemical analyses of these polysaccharides based predominantly on soluble fractions, resulted in the erroneous generalization that glucans isolated from dental plaque7 and strains of Streptococcus mutans6 89 are a-( 1 -> 6)linked dextrans. A possible therapeutic application of dextranase (a-1,6-glucan 6-glucanohydrolase, EC 3.2.1.11) was investigated in several in vitro6'9410\"2 and in vivo12-'5 studies, including clinical trials.'6-1' In vitro studies revealed that water-soluble glucans were readily cleaved by dextranase, whereas water-insoluble glucans were attacked only to a limited extent. In animal experiments, plaque formation and caries incidence were reduced only when dextranase was incorporated into a diet containing sucrose. The clinical effects of therapeutic mouthwashes containing dextranase have been discouraging. The limited ability of crude dextranase to degrade insoluble streptococcal glucans was demonstrated to be primarily a result of the lack of specificity of a-1,6-glucan 6-glucanohydrolase for insoluble glucans that were mainly a-(1 -e 3)-linked.'9'20 Dextranase produced by different strains of Penicillium, however, contained minor amounts of a-i, 3-glucan 3-glucanohydrolase, which hydrolyzed and solubilized insoluble glucans completely.'9 We decided, therefore, to search for a fungus that produces an a-(I1-> 3) gluca-

Evaluation of Left Ventricular Function from Isovolumic Pressure Measurements During Isometric Exercise

Abstract: In 24 patients left ventricular (tipmanometer) and aortic pressure measurements were carried out before and during a standardized handgrip. On the basis of findings at diagnostic cardiac catheterization, the patients were divided into 2 groups. Group 1 consisted of 13 patients without or with minimal loading of the left ventricle; group 2 comprised 11 patients with a primarily pressure-loaded left ventricle or coronary heart disease. During handgrip left ventricular systolic pressure, end-diastolic pressure and heart rate increased significantly in both groups. However, the extent of the increase of left ventricular end-diastolic pressure was considerably greater in group 2 (+8.2 mm Hg) than in group 1 (+2.0 mm Hg). Both left ventricular maximal dP/dt and the maximal quotient (dP/dt)/P, which represents a measure of the velocity of shortening of the contractile elements, increased significantly in group 1; in group 2 only maximal dP/dt increased significantly, and this increase was only about half of that observed in group 1. The time intervals from the onset of contraction to the points of maximal dP/dt and maximal (dP/dt)/P, respectively, shortened significantly during handgrip in group 1 and remained unchanged in group 2. We conclude that (1) left ventricular contractile function is impaired in patients in group 2 compared with that in group 1; (2) the primary response of the normal or near normal left ventricular myocardium to an acute load produced by handgrip is enhancement of the contractile state; and (3) the compromised left ventricular myocardium is most likely to utilize the Frank-Starling mechanism to generate increased pressure.

An algorithm for division of powerseries

Abstract: An algorithm is given to compute a solution (b 0, ...,b n) of $$\sum\limits_0^n {a_i t^i } \sum\limits_0^n {b_i t^i } \equiv \sum\limits_0^n {c_i t^i } (t^{n + 1} )$$ froma 0, ..., an, c0, ..., cn. It needs less than 7n multiplications, where multiplications with a skalar from an infinite subfield are not counted.

Molecular Basis for Repressor Activity of Qβ Replicase

Abstract: WITH the purification and characterization of viral replicases, a novel feature of nucleic acid polymerases—stringent template specificity—was recognized1,2. Qβ replicase, the most extensively studied viral RNA polymerase2–8, is now known to replicate Qβ RNA2, the complementary Qβ minus strand9, RNA molecules described as “variants” of Qβ RNA10,11, and a set of small RNAs of unknown origin which accumulate in Qβ-infected Escherichia coli, collectively designated as “6S RNA”12. On the other hand, the RNA from phages related distantly, if at all, to Qβ13,14, such as MS2 or R17, and of other viruses such as TMV2 or AMV (Diggelmann and Weissmann, unpublished results) are completely inert as templates, as are ribosomal and tRNA from E. coli2. Poly C and C-rich synthetic copolymers at high concentrations elicit synthesis which, however, remains restricted to the formation of a strand complementary to the template15,16.

Photoinduced reactions of aryl‐2H‐azirines with carbonyl compounds. Preliminary communication

Abstract: Irradiation of 3-phenyl-(4), 2-methyl-3-phenyl-(8), and 2,3-diphenyl-2H-azirine (10), in benzene solution in the presence of aldehydes, yields the corresponding aryl-3-oxazolines. Photochemical reaction of 4 and 10 with carbon dioxide leads to the formation of 4-phenyl- (15) and 2,4-diphenyl-3-oxazolin-5-one (16), respectively.

Meteorological variables affecting onset and duration of calling in Hyla arborea L. and Bufo calamita calamita Laur.

Abstract: It was the aim of this work to investigate the effects of meteorological factors on two types of behavior related to vocalization in two species of anuran amphibians (Bufo calamita and Hyla arborea). The measurements were carried out in two gravel pits in the Kanton of Zurich. Evaluation by multiple linear regression was carried out at the computer Center of Zurich University. It could be shown that water temperature at 1900 was the most important factor for the onset of callings in both species. Air pressure (for both species) and amount of rainfall on the previous day and shunshine on the same day (for Bufo calamita) played a less important but significant role for this type of behavior. In both species, water temperature at 2400 was the important factor for the duration of the mating chorus. In addition, the amount of rainfall on the previous day and sunshine on the same day had a slight but significant effect on this type of behavior in Bufo calamita. The validity of the method and the results are discussed.

Pattern Modulation and Pattern Detection in the Visual System of Hymenoptera

Abstract: In the bee, Apis mellifica, and the ant, Cataglyphis bicolor, pattern modulation and pattern detection are studied by optical methods (1) as well as by pattern discrimination tests using the training procedure (2). (1) Pattern modulation; The directional-intensity function measured by means of the light flux in a single rhabdom is characterized by a half-width of Δ ϱ = 2.6o (Apis) resp. 7.8o (Cataglyphis). In both insects, a better correlation between the directional-intensity function and the divergence angle can be found in the horizontal direction (z-axis) than in the x- and y-axes, respectively, meaning contrast transfer to be more complete in the horizontal direction. Some evaluations of contrast modulation of an array of ommatidia are given for light spots and stripe patterns by means of the optical data. (2) Pattern detection; (a) Using a simple antisymmetric intensity distribution, a vertically presented black-and-white disk with a specifically inclined contrast line, a topological central nervous representation of the visual field of the eye can be proved. (b) That system is shown not to be isotropic in function in so far as the middle lower part of the frontal visual field is most decisive for detecting contrast changes. Therefore, position-dependent weighting factors have to be introduced in any model of pattern recognition in bees. (c) The head or eye position is nearly kept constant in the flying bee, as shown by high-speed cinematography during pattern discrimination tests. Therefore, the receptor coordinates are stabilized with respect to a space-constant system. (d) The mechanism of correlating two patterns by means of overlapping and non-overlapping areas in a space-constant system, where the patterns are not allowed to rotate, cannot be the only principle in data processing due to pattern recognition: for the direction of a stripe is also detected irrespective of the sign of contrast changes (as during training or completely reversed). Therefore reduction of information may be caused by visual generalization processes.