Showing papers by "Heidelberg University published in 1974"

Bradykinin and serotonin effects on various types of cutaneous nerve fibres

Abstract: 1. Bradykinin (BKN) and Serotonin (5-HT) are endogeneous substances yielded from injured tissue and evoke pain reactions in man and animals when brought into the skin even in small quantities. In order to test which nervous elements mediate the sensations evoked by these “local hormones” we studied the spike responses of single afferent fibres in cutaneous nerves of the cat's hind leg upon intraarterial administration of small doses (5–30 μg) of 5-HT and BKN. 2. Thick myelinated, thin myelinated, and unmyelinated fibres could be excited by both substances. A further classification of the fibres was done according to the receptor types supplied by them. Among the unmyelinated fibres we tested, al receptor classes were activated by 5-HT and BKN, but among the myelinated fibres only definite groups of receptors proved to be responsive, i.e. the slowly adapting low and high threshold mechanoreceptors with thin myelinated afferents and the slowly adapting mechanoreceptors supplied by thick myelinated fibres. 3. The spike responses started 10–2- sec after injection and persisted up to 4 min in units not firing spontaneously. Discharge frequencies usually were much lower than upon physical stimulation of the receptors. 4. Repeated injection of the same agent at a rate as low as 1:15 min abolished the response to it. However this tachyphylaxis was found not to diminish the effect of the other substance. This might be an indication of an action of BKN and 5-HT on different pharmacological receptors on the nervous membranes. 5. BKN injections were found to enhance the spike discharges of unmyelinated nocipeptive fibres upon noxious radiant heat stimulation for a period of 2–5 min after a single injection of 5–30 μg. It was concluded therefrom that this agent might play a role in the hyperpathia of inflamed skin.

Pyruvate Formate‐Lyase of Escherichia coli: the Acetyl‐Enzyme Intermediate

Abstract: The reaction pyruvate + CoA ⇌ acetyl-CoA + formate, catalyzed by pyruvate formate-lyase of Escherichia coli, occurs by the succeeding half-reactions (a) E + pyruvate ⇌ E-acetyl + formate; (b) E-acetyl + CoA ⇌ E + acetyl-CoA. Making use of coupled optical assays, a ‘ping-pong mechanism’ was derived from the complete kinetic investigation of the forward and reverse reactions. The thermodynamic equilibrium constant of the overall reaction was calculated from the kinetic constants to be K= 750 (30°C, pH 8.1), which agrees with chemically determined values. The intermediate acetyl-enzyme, which had been previously proposed from the [14C]formate-pyruvate exchange, was detected by product-pulse experiments with [2-14C]pyruvate and trapped by acid precipitation. The acetyl group is linked to a sulfhydryl group of the protein. The value of the equilibrium constant of the first half-reaction is about 50, as directly measured and calculated from the kinetic data. It was concluded that the standard free energy of hydrolysis of acetyl-enzyme is about 1.7 kcal (7.1 kJ) more negative than that of acetyl-CoA. The intermediate was found to react with dithiothreitol with a second-order rate constant at 30°C and pH 7.6 of 1160 M−1× min−1. It resulted in a half-life of 4 s (or 20 s at 0°C) in the particular buffer which was required for enzyme stabilization. The enzyme (about 60 U/mg) was prepared by carrying its purified inactive form through the enzyme-II-dependent activation reaction, employing photoreduced flavodoxin along with the effector compounds S-adenosylmethionine and oxamate (as a pyruvate analogue).

Bile salt sulphates in cholestasis.

Abstract: Bile salt sulphates were determined in serum and urine of 40 patients with severe cholestasis due to extrahepatic obstruction, hepatitis, cirrhosis and metastases of the fiver Mono-, di- and tri-sulphates of bile salts were identified by column chromatography following intravenous administration of 14C-cholate Quantitative analysis was done by gas-liquid chromatography following solvolysis In our patients more than 50% of the bile salts excreted by the urine were sulphated (769% mono-sulphates, 213% di-sulphates, 18% tri-sulphates) In contrast less than 10% of serum bile salts were sulphated Therefore the renal clearance of bile salt sulphates was more than 15 times greater than the clearance of non-sulphated bile salts There were no significant differences in patients with extrahepatic obstruction, hepatitis, cirrhosis and metastases of the liver – It is concluded that urinary excretion of mono- and di-sulphates of bile salts represents an important excretory mechanism in patients with cholestatic liver disease In most patients only trace amounts of tri-sulphated bile salts were excreted in the urine

The internal order of the interphase nucleus.

Abstract: This paper has two parts. The first one is theoretical, whereas in the second, some experimenteal results are reported. Part 1: Theoretical Considerations. Comings' considerations on an ordered arrangement of chromatin in the interphase nucleus are used as a basis for further investigations and calculations in order to establish a preliminary model of the interphase nucleus. Information on the amount of DNA of a diploid human nucleus, on the degree of spiralization of chromatin threads found in electron microscopy, and measurements of salivary gland chromosomes was used to estimate the lengths of the entire interphase chromosomes. The number of fixing points-pores—was indirectly calculated proposing a model of an internal order of the chromatin threads. This number was found in concord with a direct calculation of the number of pores in the nuclear membrane based on results from electron microscopy. Part 2: Experimental Results and Discussion. In the second part of this study, an approach was made as to how to arrange chromosomes and chromosome segments in their proximity to each other. Results of cytogenetic studies of newborn babies and abortions, of cells from patients with Bloom's syndrome and Fanconi's anemia and normal cells treated with Mitomycin C and Trenimon, are thought to be informative under certain suppositions for the problem, which chromosome or chromosome parts are situated in proximity to each other. The symmetrical and equal interchanges seen, for example, in Bloom's syndrome are an indication of somatic pairing during the time of reunion. Therefore, the unequal interchanges in the same syndrome in which different chromosomes are involved should give evidence for proximity of nonhomologous chromosomes. Arguments for and against a temporal and spacial hypothesis for somatic pairing are discussed. The differing frequencies of chromosomes involved in Robertsonian translocations in man are informative for proximities of satellite regions at the nucleolus. Nucleolus and sex chromatin could be used as fixed points in a model of the interphase nucleus in which finally the absolute localization of the chromosomes will be discovered. The discussion points out promising methods for further investigations on the subject and mentions problems which could be attacked if the approach described here leads to a model of internal order in the interphase nucleus.

Optimale Lösung von Intervallgleichungssystemen

Abstract: Lineare Gleichungssysteme mit Intervallen als Koeffizienten werden untersucht. Man hat dabei zu unterscheiden zwischen der Losungsmenge und einer Intervalleinschliesung fur diese, speziell der optimalen Einschliesung. Ist die Koeffizientenmatrix des Systems einM-Matrixintervall, so kann man mit Eliminations- und Iterationsverfahren die optimale Einschliesung berechnen, bei der Elimination mus man zusatzlich nichtnegative rechte Seiten voraussetzen.

Chromosome aberrations in metaphase II-oocytes. Stage sensitivity in the mouse oogenesis to amethopterin and cyclophosphamide.

Abstract: The stage sensitivity in oogenesis of C 3 H mice was investigated by transplacental treatment of embryonic oogonia and oocytes at meiotic prophase I. After birth the stages of early and late dictyotene as well as the preovulatory and ovulatory phases were treated. Chromosome analysis was performed in unfertilized metaphase II-oocytes after induced ovulation [pregnant mare's serum (PMS) and human chorionic gonadotrophin (HCG)]. As test compounds both the folic acid antagonist amethopterin (M) and the alkylating agent cyclophosphamide (C) were used. Embryonic oogonia as well as the preovulatory phase of oogenesis proved to be most sensitive for the induction of chromosomal aberrations. The investigation with graded doses during the preovulatory stage demonstrated the dose-dependent frequency of the induced types of chromosomal abnormalities. The high sensitivity of these stages where chromosome segregation takes place, e.g. oogonia, preovulatory stage, seems to be related to an additional induction of aneuploidies.

Levelcrossing experiments in the first excited 1 P 1 states of the alkaline earths

Abstract: The hyperfine structure of the lowest1P1 state of25Mg,43Ca,87Sr,135Ba and137Ba have been measured by the level-crossing and anticrossing technique. The magnetic dipole and electric quadrupole coupling constants determined by these measurements are25Mg(3s3p1P1):A=− 7.7(5) MHz; 16 MHz>B>0 MHz,43Ca(4s4p1P1):A=− 15.3(4) MHz; ¦B¦<12 MHz,87Sr (5s5p1P1:A=− 3.4(4) MHz;B=39(4) MHz,135Ba(6s6p1P1):A=− 97.5(1.0) MHz;B=31(9)MHz,137Ba(6s6p1P1):A=−109.2(1.2) MHz;B=51(12)MHz. The results have been compared with the predictions of the Breit-Wills theory of the two-electron hyperfine structure using the experimental data on the3P states. Large discrepancies have been observed which are due to different radial wave functions of thes andp electron in the triplet and singlet system. This effect has been taken into account by fitting the data with the aid of two additional parameters. That this procedure is justified is shown by an analysis of the fine structure splitting, the life times, and the isotopic shifts in thesp configurations of group II elements.

Heteropolycyclen vom Triangulen-Typ, II. Zur Stereochemie verbrückter Triarylamine

Abstract: Nach Aussage der 1H-NMR-Spektrometrie liegt 5,5,9,9- Tetramethyl-5H, 9 H-chino[3,2,1-de]-acridin (4b), in einer C2-Konformation mit planarem Stickstoff vor, in der die beiden Acridcan-Untereinheiten entgegengesetzt gefaltet sind. Die auch bei Temperaturen von + 160°C noch nicht verbreiterten zwei Methylresonanzen beweisen eine uberraschend hohe konformative Stabilitat (ΔG≠ > 22 kcal/mol). Die entsprechenden NMR-Daten von 4,4,8,8,12,12-Hexamethyl-4H, 8H, 12H- benzol[1,9]chinolizino[3,4,5,6,7-defg]acridin (5 b) sprechen fur eine planare, oder rasch invertierende (ΔG≠ < 9 kcal/mol) flach pyramidale Struktur. Heteropolycycles of the Triangulene Type, II. The Stereochemistry of Bridged Triarylamines According to 1H-n.m.r. data, 5,5,9,9- tetramethyl-5H,9H-quino[3,2,1-de]acridine (4 b) has a C2 conformation with planar nitrogen in which the two acridane sub-entities are folded in opposite directions. The fact that the two methyl resonances do not broaden up to + 160°C proves a high conformational stability (ΔG≠ > 22 kcal/mol). The corresponding n.m.r. data for 4,4,8,8,12,12-hexamethyl-4H,8H,12H-benzol[1,9]quinolizino[ 3,4,5,6,7-defg]acridine (5 b) favour a planar or rapidly inverting (ΔG≠ < 9 kcal/mol) flat pyramidal structure.

An electron microscopic method for studying nucleic acid-protein complexes. Visualization of RNA polymerase bound to the DNA of bacteriophages T7 and T3.

Abstract: Double-stranded DNA can be readily adsorbed on mica or directly on carbon coated grids from the surface of solutions containing ethidium bromide, actinomine, or propidium diiodide. The DNA molecules are unfolded, well separated, and show a length distribution similar to molecules prepared by protein monolayer techniques. Since the intercalating dyes tested do not lead to an increased apparent diameter of the nucleic acid the method is useful for the study of nucleic acid–protein complexes. As a model, the binding of E. coli RNA polymerase to phage T7 and T3 DNA was examined under different conditions. The enzyme can easily be identified and its position along the DNA molecule can be mapped.

Escherichia coli Ferredoxin, an Iron‐Sulfur Protein of the Adrenodoxin Type

Abstract: Ferredoxin of Escherichia coli is an iron-sulfur protein of the molecular weight about 12000 which contains two iron and two labile sulfur atoms. The sequence of the amino terminus is HN-Pro-Lys-Val-Ile-Val-Leu-Tyr-. The electron paramagnetic resonance spectrum of the reduced form shows a low-field signal with g∥= 2.02 and a single high-field signal with g⊥= 1.94. From the circular dichroism spectrum in the peptide absorption region an amount of 10% helically ordered regions is computed. A new peak in the light absorption spectrum at 545 nm appears upon reduction. From the spectral data, which reflect the fine structure of the chromophore and the gross conformation of the polypeptide chain, a close relationship to the mitochondrial adrenodoxin is concluded. The midpoint potential of the protein is –0.38 V. It does not mediate electron transport in the NADP-photoreduction system of spinach and is incapable of replacing the Pseudomonas putida ferredoxin in the camphor hydroxylation. The physiological role of this ferredoxin, which is not a functional analogue of the Escherichia coli flavodoxin and which is synthesized by aerobically as well as anaerobically growing cells, is unknown.

The intrinsic brain iso-renin--angiotensin system in the rat: its possible role in central mechanisms of blood pressure regulation.

Abstract: 1. Angiotensin is produced by the intrinsic iso-renin-angiotensin system. 2. Angiotensin is secreted into the cerebrospinal fluid of nephrectomized rats. 3. Angiotensin in cerebrospinal fluid elevates systemic blood pressure. 4. Rats with hereditary diabetes insipidus are virtually non-responsive to intraventricular angiotensin. 5. Angiotensin II is elevated in the cerebrospinal fluid of spontaneously hypertensive rats. 6. An intraventricular perfusion of the angiotensin II receptor-blocking agent P 113 decreases blood pressure in spontaneously hypertensive rats.

Plasmids Controlling Synthesis of Hemolysin in Escherichia coli: Molecular Properties

Abstract: Covalently closed extrachromosomal deoxyribonucleic acid (DNA) was isolated from alpha-hemolytic wild-type strains of Escherichia coli . Most strains examined were able to transfer the hemolytic property with varying frequencies to nonhemolytic recipient strains. Out of eight naturally isolated alphahemolytic E. coli strains, four contained a set of three different supercoiled DNAs with sedimentation coefficients of 76 S (plasmid A), 63 S (plasmid B), and 55 S (plasmid C). The sedimentation coefficients and the contour lengths of the isolated molecules correspond to molecular weights of 65 × 10 6 , 41 × 10 6 , and 32 × 10 6 . Three alpha-hemolytic wild-type strains carried only one plasmid with a molecular weight of 41 × 10 6 , and one strain harbored two plasmids with molecular weights of 41 × 10 6 and 32 × 10 6 . Alpha-hemolytic transconjugants were obtained by conjugation of E. coli K-12 with the hemolytic wild-type strains. A detailed examination revealed that plasmids with the same sizes as plasmids B and C of the wild-type strains can be transferred separately or together to the recipients. Both plasmids possess the hemolytic determinant and transfer properties. Plasmid A appears to be, at least in one wild-type strain, an additional transfer factor without a hemolytic determinant. In one case a hemolytic factor was isolated, after conjugation, that is larger in size than plasmid A and appears to be a recombinant of both plasmids B and C. Images

Reflexes in postganglionic fibres within skin and muscle nerves after noxious stimulation of skin.

Abstract: 1. Somomato-sympathetic reflexes in postganglionic neurones to skin and muscle induced by noxious stimulation of skin were studied in cats anaesthetized with chloralose. The reflexes were elicited by mechanical damaging stimuli and by temperature stimuli of more than 45°C. 2. In most cutaneous units the spontaneous activity was depressed during noxious stimulation of skin. Some cutaneous units were excited or showed mixed responses. The depression of the spontaneous activity was maximal from the skin area which was innervated by the cutaneous postganglionic neurones and much weaker or not elicitable from other skin areas. 3. Most muscle units were excited during noxious stimulation of skin. This excitation could be elicited from all over the body surface. 4. The effective cutaneous afferent fibres which are involved in these reflexes are the Group III axones which are excitable by mechanical damaging stimuli and the Group IV axones which are excitable by mechanical damaging and/or by thermal noxious stimuli. 5. These investigations reveal that the somato-sympathetic reflexes have opposite organization in cutaneous and muscle postganglionic fibres. The reflex patterns are discussed in relation to a possible central organization of the sympathetic nervous system.

Thomas-Fermi and Thomas-Fermi-Dirac calculations for atoms in a very strong magnetic field

Abstract: A statistical model for atoms in a very strong magnetic field (${10}^{12}$-${10}^{14}$ G) may be built, starting from the assumption that the Coulomb motion of the atomic electrons is adiabatically slow with respect to their magnetic motion. Within this framework, the binding energies and radii, as well as the ionization energies of singly and doubly ionized atoms, are computed for atomic numbers $5\ensuremath{\le}Z\ensuremath{\le}100$ in the Thomas-Fermi case, and for $5\ensuremath{\le}Z\ensuremath{\le}70$ in the Thomas-Fermi-Dirac case. Possible astrophysical implications may concern the emission of electrons and ions from the surface of pulsars, the abundances of the elements in the cosmic radiation, and the properties of the condensed matter forming the outer crust of magnetic neutron stars.

Morphological studies on pathogenesis of epiphyseal slipping in uremic children.

Abstract: The epiphyseal growth plate of femora (proximal and distal), tibiae, radii and ulnae of seven uremic children were studied to clarify the histopathogenesis of epiphyseolysis. Epiphyseolysis was found to be result of three different processes: (1) growth arrest, (2) excessive erosion of the growth cartilage and of the trabeculae of metaphyseal spongiosa and (3) disturbance of vascularisation of hypertrophic cartilage. By resorptive destruction, secondary hyperparathyroidism causes loss of the chondro-osseous continuity. The ordered trajectoral pattern of the trabeculae in the primary spongiosa is transformed into a dense lace of mechanically inferior trabeculae consisting of woven bone. Impairment of primary mineralization could not be demonstrated. Intensive subperiosteal osteoclastic resorption leads to a reduction of metaphyseal width and to fractures of the unsupported lateral parts of the growth cartilage. There were notable differences between the growth plates in different localisations: in growth plates subjected to axial compression (distal femur, tibia) signs of growth arrest prevailed (reduction of hypertrophic cartilage, occlusion of the growth plate by a transverse plate of bone); in growth plates subjected to shearing forces (upper femur, radius, ulna) epiphyses were seen to slip sideway.

The ultrastructure of the thin loop limbs of the mouse kidney.

Abstract: The thin limbs of the loops of Henle in the mouse kidney have been investigated by conventional electron microscopy. Resulting from light microscopic investigations, a distinction in the epithelia of short and long loops can be demonstrated. Ultrastructurally, the thin limbs (descending) of short loops are composed of a uniformly thin and simple epithelium. In contrast, long loops (thin descending and ascending) are composed of three different epithelial types which are representative of a distinctly more complex epithelial system. Two epithelial types were observed in the thin descending limbs of long loops and the third type was observed in the ascending thin limbs. Based upon these findings it is suggested that the thin descending limbs of short and long loops of Henle in the mouse kidney cannot perform the same functions in the renal concentrating mechanism.

Isolation and culture of tobacco mesophyll protoplasts using a saline medium

Abstract: A new method is proposed for the isolation of tobacco mesophyll protoplasts in which salts were used as the plasmolyticum instead of the traditionally applied sugars. With this method protoplasts were regularly obtained and practically independent of the physiological state of the plants. In addition, a salt medium was developed in which the majority of protoplasts dedifferenciate and divide at a developmental state in which no wall could be detected by plasmolysis. After transferring these cells into another medium they were able to regenerate a wall and to divide.

Reaktionen des Bis‐trimethylsilyl‐schwefeldiimids zur Darstellung neuer Schwefel‐Stickstoff‐Verbindungen

Abstract: Die Reaktion des R3SiNSNSiR3 (1) [R = CH3] mit Chlor fuhrt zum R3SiNSNCl (3). Mit Trifluoracetylchlorid erhalt man aus 1 CF3CO(S3N3) und mit Schwefeldichlorid S(NSNSiR3)2 (5), welches sich mit weiterem Schwefeldichlorid unter Ringschlus zu S4N4 umsetzt. Eine gunstige Darstellungsmethode fur S(NSiR3)3 (6) wird mitgeteilt. Durch ESCA-Spektren werden die Bindungsverhaltnisse in 5 zu ermitteln versucht. Reactions of (CH3)3SiNSNSi(CH3)3 for Preparation of New Sulfur-Nitrogen Compounds R3SiNSNSiR3 (1) [R = CH3] and chlorine react under formation of R3SiNSNCl (3). From 1 and trifluoromethyl acetylchloride CF3CO(S3N3) is obtained, and 1 with sulfur dichloride yields S(NSNSiR3)2 (5). This compound reacts with SCl2under formation of S4N4. A new method for the preparation of S( = NSiR3)3 (6) is given. Investigation of the chemical bonds of 5 by ESCA measurements was tried.