Showing papers by "University of Freiburg published in 1983"

A papillomavirus DNA from a cervical carcinoma and its prevalence in cancer biopsy samples from different geographic regions.

Abstract: DNA from one biopsy sample of invasive cancer of the cervix contained sequences hybridizing with human papillomavirus (HPV) type 11 DNA only under nonstringent conditions. This DNA was molecularly cloned in lambda phage. Under stringent conditions of hybridization it cross-hybridized to a minor extent (less than 0.1%) with HPV types 10, 14, and 15 and showed no homology with DNA of other human HPV types. We therefore propose to designate it tentatively as HPV 16. HPV 16 DNA was used as a probe to test additional cancer biopsy samples from cervical, vulval, and penile cancer, as well as benign genital warts (condylomata acuminata) and cervical dysplasias for the presence of homologous sequences. In 61.1% (11/18) of cervical cancer samples from German patients sequences were found hybridizing with HPV 16 DNA under conditions of high stringency. In contrast, only 34.8% (8/23) of cancer biopsy samples from Kenya and Brazil revealed this DNA. Vulval and penile cancer biopsy samples hybridized to 28.6% (2/7) or 25% (1/4), respectively. Only 2 out of 33 condylomata acuminata contained HPV 16 DNA. Both positive tumors harbored in addition HPV 6 or HPV 11 DNA. The data thus indicate that HPV 16 DNA prevails in malignant tumors, rendering an accidental contamination with papillomavirus DNA from adjacent papillomas rather unlikely. The rare presence in benign genital papillomas in addition to common genital papillomaviruses suggests a dependence of HPV 16 replication on helper virus.

Human papillomavirus types 6 and 11 DNA sequences in genital and laryngeal papillomas and in some cervical cancers

Abstract: Human genital tumors as well as recurrent laryngeal papillomas were analyzed for the presence of human papillomavirus (HPV) 6 and HPV 11 sequences. HPV 11 DNA was found in 7 of 14 laryngeal papillomas; in the 7 other tumors no HPV DNA was demonstrated. HPV 11 DNA was also found in all five atypical condylomata of the cervix included in this study. Condylomata acuminata mainly contained HPV 6 DNA. From 63 biopsy specimens, 41 clearly harbored HPV 6 DNA and 13 harbored HPV 11 DNA. In three tumors accurate typing was impossible, and in six additional ones neither HPV 6 nor HPV 11 DNA could be demonstrated. The data support a genital origin of laryngeal papillomavirus infections. In 4 of 24 malignant tumors, HPV 11 DNA or related sequences were demonstrated; 2 of the 4 were biopsy specimens from invasive cancer, and the other 2 originated from carcinomata in situ. A possible role of this or related papillomavirus types in the induction of malignant genital tumors remains to be elucidated.

Static and dynamic light scattering from branched polymers and biopolymers

Abstract: The striking properties of synthetic polymers and biological macromolecules are largely determined by their shape and the internal mobility. Both quantities are closely related to the architecture of the molecules. This article deals with branched macromolecules in dilute solution, where the individual molecules are observed. The common technique for determining the shape of macromolecules is static light scattering. Information on the internal mobility and the translational motion of the mass centre can be obtained from the more recent technique of quasi-elastic or dynamic light scattering.

Human papillomavirus type‐16‐related DNA in genital Bowen's disease and in bowenoid papulosis

Abstract: 32P-labelled DNA of HPV 16 which has been isolated and molecularly cloned from a cervical carcinoma (Durst et al, 1983) was used to screen the cellular DNAs obtained from 20 different biopsies of Morbus Bowen or Bowenoid papulosis, respectively, by Southern blot analysis Under conditions of differing stringency for the hybridization, HPV 16 DNA or related sequences were identified in 6 out of 10 cases of Morbus Bowen (4 out of 5 from a genital localization) and in 8 out of 10 biopsies from Bowenoid papulosis One additional case of the latter disease contained DNA sequences of an HPV type not yet classified There is evidence for the presence of another HPV DNA in two of the HPV-16-positive tumors A large number of normal genital tissue samples were negative for HPV DNA

Valuations on convex bodies

Abstract: The investigation of functions on convex bodies which are valuations, or additive in Hadwiger’s sense, has always been of interest in particular parts of geometric convexity, and it has seen some progress in recent years. The occurrence of valuations in the theory of convex bodies can be traced back to the notion of volume in two essentially different ways. Firstly, the volume of convex bodies, being the restriction of a measure, is itself a valuation. This valuation property carries over to the functions which are deduced from volume in the Brunn-Minkowski theory, namely to mixed volumes, quermassintegrals, surface area functions, and others. Hadwiger’s celebrated characterizations of the quermassintegrals by the valuation and other properties were the culmination of a series of papers on valuations and at the same time the starting point for various subsequent investigations of functionals with similar properties.

Zonoids and Related Topics

Abstract: A zonoid is a convex body in euclidean space which can be approximated, in sense of the Hausdorff metric, by finite vector sums of line segments Several equivalent definitions are known, and zonoids appear in some surprisingly different contexts The purpose of the present survey article is twofold After giving some basic definitions and properties of zonotopes and zonoids, we describe the various ways in which zonoids enter the discussion of a number of seemingly unrelated topics The stress is here on interrelations between the geometry of convex bodies and other fields The second part treats those results and problems concerning zonoids and their generalizations which are of interest within the theory of convex bodies

Genetic evidence that a Y-linked gene in man is homologous to a gene on the X chromosome.

Abstract: The mammalian sex chromosomes are thought to be related to each other by sharing a common origin. That is, the X and Y chromosomes originally evolved from a pair of chromosomes that only differed at the locus determining sexual differentiation1,2. For example, this evolutionary relationship is reflected during meiosis3 in chromosomal pairing between the tip of the human X chromosome short arm and the Y chromosome which presumably implies sequence homology4. However, compelling genetic evidence for functional homology between the mammalian X and Y chromosome is lacking. We describe here the localization of a gene to the tip of the short arm of the human X chromosome and evidence for a related gene on the Y chromosome.

Investigation of the Primary Photochemistry of Bacteriorhodopsin by Low‐Temperature Fourier‐Transform Infrared Spectroscopy

Abstract: The method of Fourrier-transform infrared difference spectroscopy was applied to investigate the transition at 77K of bacteriorhodopsin in its light-adapted form to K610, the first intermediate which is stable at low temperature. In addition to unmodified bacteriorhodopsin, bacteriorhodopsin in 2H2O and bacteriorhodopsin containing [15-2H]retinal was used. The results show that major rearrangements occur in the Schiff base in this transition. It is not possible to identify a C=N stretching vibration of the Schiff base in K610. The identification of an N-H bending vibration in K610 shows that the nitrogen of the previous Schiff base still has a proton attached. The fingerprint region exhibits very unusual features for K610 and bears no similarity to protonated retinylidene Schiff base model compounds of any isomeric composition. Therefore, no conclusions on the isomeric state of the retinal in K610 can be drawn. The spectra show that the terminal part of the retinal is predominantly reflected in the difference spectra. This indicates that the most polar part of the retinal is located near the Schiff base. We have evidence for protein molecular changes occurring in this transition at 77K.

Endothelial cells are involved in the vasodilatory response to hypoxia

Abstract: The role of endothelial cells in the dilatory response of arteries to hypoxia was studied in vitro using perfused arterial segments of rat and dog. The pO2 of the intra- and extraluminal perfusate could be varied separately. Intraluminal hypoxia (pO2 of 40 mmHg) induced a dilation irrespective of extraluminal pO2 level. On the contrary, extraluminal hypoxia could not elicit a dilation during intraluminal normoxic perfusion. Dilation during extraluminal hypoxia could only be induced if the segment was not intraluminally perfused. The dilatory response to intraluminal hypoxia was abolished after enzymatical or mechanical removal of the endothelium. While theophylline and lipoxygenase inhibitors did not influence this endothelium-induced dilation, a significant reduction of the response could be observed after incubation with indomethacin. These results support the concept that prostacyclin (PGI2) might be involved in the hypoxic endothelium-induced dilation.

Sonographic biometry of liver and spleen size in childhood.

Abstract: In 194 healthy children of all ages, sonographic measurements of the liver and spleen were performed on standardized section planes and normal values established. These measurement values showed an approximately linear increase in the course of development and correlated best with the body length. For a rapid orientational evaluation of the liver size, sonographic nomograms of the individual measurements were developed. The spleen size was determined by volume calculation. On the basis of an index of liver size, which was calculated from the individual measurements, a diagram for simultaneous determination of liver and spleen size could be developed. These nomograms permit objective morphometry of size changes in the two organs.

Differential response of cultured parsley cells to elicitors from two non-pathogenic strains of fungi. 1. Identification of induced products as coumarin derivatives.

Abstract: Dark-grown cell suspension cultures of parsley, Petroselinum hortense, produce furanocoumarins after treatment with elicitor preparations of either Phytophthora megasperma f.sp. glycinea (Pmg elicitor) or Alternaria carthami Chowdhury (Ac elicitor). The linear furanocoumarins, psoralen and xanthotoxin, and the benzodipyrandione, graveolone, are the major products synthesized in response to Pmg elicitor, besides small amounts of the furanocomarin bergapten. Treatment with Ac elicitor induces predominantly the formation of bergapten and the furanocoumarin isopimpinellin, as well as small amounts of graveolone. While Pmg elicitor leads to cell death within a few days, cell mass increased for at least 6 days after treatment with Ac elicitor. Brefeldin A, a phytotoxin produced by A. carthami, inhibits growth of parsley cell suspension cultures considerably at a concentration of 0.01 mM and growth of the cells ceased at a concentration of 0.1 mM toxin. Concomitantly, furanocoumarin biosynthesis was suppressed in our system by a concentration of brefeldin A within 0.01–0.1 mM.

Light gradients in plant tissue

Abstract: In this paper we suggest a method for calculating light gradients in scattering and absorbing media. The method is based on the Kubelka-Munk theory and involves computational modeling of light fluxes in a multilayered object, when every layer satisfies the prerequisites of the Kubelka-Munk theory. The model also includes specular reflection that may contribute strongly to internal photon fluence rates for diffuse light. To illustrate the possible effects of light gradients, a cotyledon of Cucurbita pepo is described in terms of this model. It is argued that a number of results in in vivo spectroscopy cannot be correctly interpreted unless light gradients or optics in general are included in the discussion, i.e., the light flux at the site of the pigment has to be known. To outline the difficulties involved some methods of measuring light gradients or internal photon fluence rates are critically considered.

Basic Metal Cluster Reactions

Abstract: Publisher Summary This chapter discusses basic metal cluster reactions Addition or removal of electrons, the simplest type of chemical reaction, is much more common for transition metal than for main group element compounds Among the metal complexes, the clusters are predestined for this process Possible unidentate reagents are atomic cations and other simple electrophiles as well as atomic anions and other simple nucleophiles All cluster syntheses involve growth or fragmentation of metal atom aggregates But until very recently, the buildup of clusters or the use of clusters as fragment sources involved empirical approaches with little predictability The 18-electron rule generally governs the bonding in clusters with up to five metal atoms Clusters with five, six, and sometimes seven metal atoms can often be treated in terms of skeletal electron counting, describing the frameworks by the nido, closo, and capping formalisms A systematization of basic cluster reactions has been attempted based on the present status of knowledge The number of reactions reported is still relatively small for certain reaction types

On the history of the kronecker product

Abstract: History reveals that what is today called the Kronecker product should be called the Zehfuss product.

Further functional in vitro comparison of pre- and postsynaptic dopamine receptors in the rabbit caudate nucleus.

Abstract: Slices of the rabbit caudate nucleus were preincubated with 3H-dopamine or 3H-choline and then superfused and stimulated electrically. DiPr-5,6-ADTN reduced the stimulation-evoked overflow of tritium over the same concentration range, independently of whether slices had been preincubated with 3H-dopamine or 3H-choline, and the same was true for apomorphine, NPA and pergolide. Three other putative dopamine receptor agonists, namely 3-PPP, DPI and SKF 38393, failed to decrease the evoked overflow of tritium. Each of six antagonists — (−)-sulpiride, (+)-sulpiride, CGP 11109 A, cis-flupentixol, domperidone and corynanthine —increased the evoked overflow over the same concentration range in experiments with 3H-dopamine and in those with 3H-choline. For each of these antagonists except cis-flupentixol, and also for chlorpromazine, haloperidol and rauwolscine, the pA2 values against apomorphine obtained in 3H-dopamine and in 3H-choline experiments were closely similar. The antagonist effect of cis-flupentixol against apomorphine was not purely competitive. (−)-Sulpiride was a more potent antagonist than (+)-sulpiride, and cis-flupentixol was more potent than trans-flupentixol.

Photooxidative destruction of chloroplasts and its consequences for cytosolic enzyme levels and plant development.

Abstract: Mustard (Sinapis alba L.) seedlings were grown in the presence of herbicides (Difunon, Norflurazon) which inhibit carotenoid synthesis without affecting development, in darkness or in continuous far-red light. In strong white light (12,000 lx) the cotyledons of the herbicide-treated seedlings did not contain normal chloroplasts, but only small chlorophyll-free rudiments whose internal structure had almost disappeared. The plastid marker enzyme NADP-dependent glyceraldehyde-3-phosphate dehydrogenase was almost lacking. Plastid ribosomes and ribosomal RNAs were no longer detectable nor could synthesis of mature plastidal ribosomal RNAs be detected. Cytosolic ribosomes and rRNAs were not affected. Plastid DNA was apparently still intact as shown by restriction analysis. The appearance of marker enzymes of glyoxisomes, mitochondria and cytosol was not impaired while the level of marker enzymes of peroxisomes was drastically lowered. Accumulation of anthocyanin in mustard cotyledons was normal after a short, transient delay. Levels of representative enzymes of flavonoid biogenesis (phenylalanine ammonia-lyase, chalcone synthase) were somewhat increased rather than inhibited in the cotyledons of herbicide-treated, white-light-grown seedlings. The growth rate of hypocotyl and cotyledons was inhibited to the same extent in the herbicide-treated, white-light-grown seedling, although light inhibits growth of hypocotyls and promotes growth of cotyledons. Analysis of the data shows that photomorphogenesis of a herbicide-treated, white-light-grown seedling is normal, and is thus independent of plastid gene expression However, a ‘factor’ which coacts multiplicatively with phytochrome in determining the growth rate of the organs seems to originate from the plastids. Biogenesis of anthocyanin and synthesis of major enzymes of the flavonoid pathway are not affected adversely by a photooxidative elimination of plastid gene expression.

Dopamine modulates cholecystokinin release in neostriatum.

Abstract: Peptides of the cholecystokinin family, but mainly the sulphated octapeptide (CCK8), have been found in brain extracts of several species1–6. High amounts are present in axons and nerve endings in the rat neostriatum (caudate-putamen)7,8 and a role for cholecystokinin as a neurotransmitter in this functionally important area is possible9,10. We have incubated slices of rat caudate-putamen (CP) to study the release of cholecystokinin-immunoreactivity (CCK-IR) in vitro. The release of CCK-IR was induced by veratridine. It was dependent on the presence of Ca2+ in the incubation medium and was blocked by tetrodotoxin. We now present evidence that dopaminergic agonists added to the slices modulate the veratridine-induced release via different groups of receptors. Receptors which mediate an enhancement of the release of CCK-IR seem to be located on afferent axons and nerve endings and are possibly of the D-2 subtype. Receptors which mediate an attenuation of the release are probably situated on cells intrinsic to the CP. These receptors seem to be coupled to adenylate cyclase and might thus be of the D-1 subtype. There is also evidence that endogenous dopamine when released enhances the secretion of CCK-IR.

Phenol coupling initiated by one-electron oxidation of tyrosine units in peptides and histone.

Abstract: SummaryPhenoxyl radicals generated pulse radiolytically by the reaction of N·3 with Gly-Tyr decay bimolecularly (2k = 4·7 × 108 M−1 s−1) with efficient formation of 2,2′-dimers, which enolize rapidly (k = 2·7 × 104 s−1) to produce the 2,2′-biphenolic product. The build-up of the characteristic 2,2′-biphenol fluorescence (400 nm) and absorption also indicated a delayed (k = 80 s−1) process, probably involving the phenoxyl ↔ phenoxy-quinol equilibrium. About 60 per cent of the Gly-Tyr phenoxyls were found to dimerize to the 2,2′-biphenol, and a similarly efficient 2,2′-coupling seems to occur with other tyrosyls, such as Lys-Tyr-Lys and histone. γ-Radiolysis was applied to estimate relative yields of formation of 2,2′-biphenols under various conditions. Dimerization is almost completely inhibited by cysteine or oxygen, consistent with phenoxyl ‘repair’ by cysteine or ; disproportionation of with SOD prevents repair. The phenol 2,2′-coupling is less efficient for ·OH- and inefficient for e−aq-initiation.

Induction and Characterization of a Microsomal Flavonoid 3′-Hydroxylase from Parsley Cell Cultures

Abstract: A microsomal preparation from irradiated parsley cell cultures catalyses the NADPH and dioxygen-dependent hydroxylation of (S)-naringenin [(S)-5, 7, 4'-trihydroxyflavanone] to eriodictyol (5, 7, 3', 4'-tetrahydroxyflavanone). Dihydrokaempferol, kaempferol, and apigenin were also substrates for the 3'-hydroxylase reaction. In contrast prunin (naringenin 7-O-beta-glucoside) was not converted by the enzyme. The microsomal preparation, which also contains cinnamate 4-hydroxylase, did not catalyse hydroxylation of 4-coumaric acid to caffeic acid. 3'-Hydroxylase activity is partially inhibited by carbon monoxide in the presence of oxygen as well as by cytochrome c and NADP+. These properties suggest that the enzyme is a cytochrome P-450-dependent flavonoid 3'-monooxygenase. Pronounced differences in the inhibition of flavonoid 3'-hydroxylase and cinnamate 4-hydroxylase were found with EDTA, potassium cyanide and N-ethylmaleimide. Irradiation of the cell cultures led to increase of flavonoid 3'-hydroxylase activity with a maximum at about 23 h after onset of irradiation and subsequent decrease. This is similar to light-induction of phenylalanine ammonialyase and cinnamate 4-hydroxylase. In contrast, treatment of the cell cultures with a glucan elicitor from Phytophthora megasperma f. sp. glycinea did not induce flavonoid 3'-hydroxylase nor chalcone isomerase but caused a strong increase in the activities of phenylalanine ammonia-lyase, cinnamate 4-hydroxylase, and NADPH--cytochrome reductase. The results prove that flavonoid 3'-hydroxylase and cinnamate 4-hydroxylase are two different microsomal monooxygenases.

Fourier-transform infrared spectroscopy applied to rhodopsin. The problem of the protonation state of the retinylidene Schiff base re-investigated.

Abstract: By measuring the rhodopsin--bathorhodopsin, isorhodopsin--bathorhodopsin, rhodopsin--isorhodopsin and rhodopsin--meta-II difference spectra with the method of Fourier-transform infrared spectroscopy we have identified the C = N stretching vibration of the protonated retinylidene Schiff base of rhodopsin, isorhodopsin and bathorhodopsin. In contrast to resonance Raman spectroscopy additional strong bands were observed between 1700 cm-1 and 1620 cm-1. Most of them depend on the isomeric state of the chromophore. The origin of these bands will be discussed. In the fingerprint region isorhodopsin and bathorhodopsin are quite similar but no similarities with infrared spectra of model compounds of any isomeric composition are observed. Therefore, no conclusions on the isomeric state of the retinal in bathorhodopsin can be drawn. We provide evidence for the modification of one or two carboxylic group(s) during the rhodopsin--bathorhodopsin and isorhodopsin--bathorhodopsin transition.

Charged states in ℤ2 gauge theories

Abstract: Charged translation covariant states with finite energy are constructed in the Higgs phase of the ℤ2 gauge theory coupled to a ℤ2 matter field.