Showing papers by "Humboldt University of Berlin published in 1988"
TL;DR: The mechanism of reversible electric breakdown of lipid membranes is studied and hydrophilic pores of an effective radius of 0.6 up to more than 1 nm are formed, which account for the membrane conductivity increase observed.
558 citations
235 citations
106 citations
TL;DR: The construction of a new heteromyeloma cell line derived from xenogeneic somatic cell hybridization between normal human B lymphocytes and the murine HAT-sensitive P3X63Ag8/653 cell line and the generation of hybrids secreting human monoclonal antibodies to human immunodeficiency virus is described.
101 citations
TL;DR: Analysis of results 1 to 3 years after therapy revealed the ineffectiveness of 89Sr to relieve pain from metastases and a higher survival rate was found after Sr application.
Abstract: Forty-nine patients were treated with either 3×75 MBq 89Sr or saline as placebo. Analysis of results 1 to 3 years after therapy revealed the ineffectiveness of 89Sr to relieve pain from metastases. Unexpectedly, a higher survival rate was found after Sr application (46% vs 4% after 2 years). Covariate analysis underlines the effect of 89Sr therapy on life expectation.
96 citations
TL;DR: 3'-fluorothymidine (FddThd) protects 50% of the MT-4 cells against the cytopathic effect of HIV at 3 nM, but reduces the number of uninfected viable cells to 50% at 1.1 microM, and all other tested human cell-lines displayed a far less antiproliferative sensitivity to Fdd Thd, comparable with that of AzT.
87 citations
TL;DR: In this article, the functionality of two high-mucilage protein concentrates (HMPC) prepared from linseed and linseed expeller cake by extracting and coprecipitating the mucilage with protein was compared with those of a low mucilage flour (LMF), a protein concentrate (LMPC), and a protein isolate (LMPI) in simple systems.
Abstract: The functionality of two high-mucilage protein concentrates (HMPC) prepared from linseed and linseed expeller cake by extracting and coprecipitating the mucilage with protein was compared with those of a low-mucilage flour (LMF), a protein concentrate (LMPC), and a protein isolate (LMPI) in simple systems. The HMPC samples had better water absorption and emulsifying properties, higher foaming capacity, but lower nitrogen solubility, oil absorption, and foam stability than LMF and LMPC. They also registered higher values of viscosity and emulsification characteristics than LMPI.
79 citations
TL;DR: N-Acetyl-beta-D-glucosaminidase was the analyte most often increased in group A (89%), followed by albumin and alkaline phosphatase (each 32%), and all patients in group B showed increased excretion of N-acetyl- beta- D-glUCosaminidsase, which may be useful as an early predictor of diabetic nephropathy.
Abstract: We measured the excretion rates of six urinary enzymes that either originate from the proximal renal tubule, like alanine aminopeptidase (EC 3.4.11.2), alkaline phosphatase (EC 3.1.3.1), gamma-glutamyltransferase (EC 2.3.2.2), and N-acetyl-beta-D-glucosaminidase (EC 3.2.1.30), or that are typical low-molecular-mass proteins, like lysozyme (EC 3.2.1.17) and pancreatic ribonuclease (EC 3.1.27.5). These rates were compared with those of total protein and albumin in urine of 36 insulin-dependent diabetic men and 30 healthy men. Seventeen of the diabetics had "clinical proteinuria," defined as excretion of more than 7.5 g of protein per mole of urinary creatinine (group B). Group A comprised the 19 diabetics without proteinuria. Except for gamma-glutamyltransferase, the excretions of enzymes and proteins were significantly higher in diabetics than in controls and were greater in group B than in group A. N-Acetyl-beta-D-glucosaminidase was the analyte most often increased in group A (89%), followed by albumin and alkaline phosphatase (each 32%). All patients in group B showed increased excretion of N-acetyl-beta-D-glucosaminidase. We conclude from the comparative data that this enzyme may be useful as an early predictor of diabetic nephropathy.
75 citations
TL;DR: The timeless modernity and topicality of Rudolf Virchow's postulations on tumor pathology is based on his general conclusions which as key propositions have retained general validity throughout more than a century.
Abstract: Rudolf Virchow (1821-1902), the great German pathologist of the 19th century, founder of the "Zellularpathologie", also dealt with principal problems of tumor pathology. His theoretical concepts concern the definition and characterization of the tumor process, the dignity and diagnosis, published especially in his 3 monographs "Die Entwicklungsgeschichte des Krebses" (1847), "Handbuch der speciellen Pathologie und Therapie" (1854) and "Die krankhaften Geschwulste" (1863-65). The achievements of Rudolf Virchow are not related to the description and diagnosis of specific tumors together with their genesis and interpretation. There have been quite a few errors and false concepts which can longer be accepted today. The timeless modernity and topicality of Rudolf Virchow's postulations on tumor pathology is based on his general conclusions which as key propositions have retained general validity throughout more than a century. They have been confirmed and further interpreted by knowledge which has been accumulated largely over the past one or two decades in the fields of tumor research, electron microscopy, molecular biology, genetics, and immunology.
68 citations
TL;DR: An enzyme immunoassay for the quantification of human Cu/Zn SOD in serum, urine and erythrocytes was developed applying monoclonal and polyclonal antibodies, and patients with Down's syndrome exhibited a 3.8-fold, a 2-fold and a 1.6-fold higher concentration than healthy individuals.
45 citations
TL;DR: A mathematical model is presented which comprises the reactions of glycolysis, the hexose monophosphate shunt (HMS) and the glutathione system in erythrocytes and is used to calculate stationary and time-dependent metabolic states of the cell in vitro and in vivo.
Abstract: A mathematical model is presented which comprises the reactions of glycolysis, the hexose monophosphate shunt (HMS) and the glutathione system in erythrocytes. The model is used to calculate stationary and time-dependent metabolic states of the cell in vitro and in vivo. The model properly accounts for the following metabolic features observed in vitro: (a) stimulation of the oxidative pentose pathway after addition of pyruvate due to a NADP-dependent lactate dehydrogenase as coupling enzyme between glycolysis and the oxidative pentose pathway, (b) relative share of the oxidative pentose pathway in the total consumption of glucose amounting to approximately 10% in the normal case and to approximately 90% under conditions of oxidative stress excreted by methylene blue. From the application of the model to in vivo conditions it is predicted that (c) under normal conditions glycolysis and the HMS are independently regulated by the energetic and oxidative load, respectively, (d) under conditions of enhanced energetic or oxidative load both glycolysis and the HMS are mainly controlled by the hexokinase; in this situation the highest possible values of the energetic and oxidative load which are compatible with cell integrity are strongly coupled and considerably restricted in comparison with the normal case, (e) the stationary states possess bifurcation points at high and low values of the energetic load.
Patent•
04 Feb 1988TL;DR: Safety biopsy forceps as mentioned in this paper include operating forceps, a flexible shaft, a pulling element, as well as a head with cutting-and/or grasping elements, of which at least one element is moveable by means of the pulling element.
Abstract: Safety biopsy forceps, in particular for infants, comprise operating forceps, a flexible shaft, a pulling element, as well as a head with cutting- and/or grasping elements, of which at least one element is moveable by means of the pulling element, provided with a head with cutting- and/or grasping element which is detachably fastened on the flexible shaft. The flexible shaft is detachably fastened to the operating forceps and the pulling element to the operating forceps. The pulling element is adjustable for the setting of the cutting- and/or grasping elements and the setting of the force of the cutting process and can also be locked in after the adjustment. The cutting- and/or grasping elements are provided at the joint with a recess which prevents tissue from becoming lodge during closing of the elements.
29 Aug 1988
TL;DR: Mammary‐derived growth inhibitor (MDGI), a polypeptide growth inhibitor isolated from lactating bovine mammary tissue, was demonstrated to meet the criteria of a fatty acid‐binding protein, and was found to bind [3H]palmitic acid in a saturable manner and to be complexed with endogeneous free fatty acids.
Abstract: Mammary-derived growth inhibitor (MDGI), a polypeptide growth inhibitor isolated from lactating bovine mammary tissue, previously shown to have extensive sequence homology with fatty acid-binding proteins, was demonstrated to meet the criteria of a fatty acid-binding protein. The protein was found to bind [3H]palmitic acid in a saturable manner and to be complexed with endogeneous free fatty acids. [3H]palmitic acid, when bound to the protein, was more rapidly taken up by the target cells (human mammary carcinoma cells [MaTu]) than was free [3H]palmitic acid, suggesting a lipid carrier function for the inhibitor. It is suggested that the fatty acid-binding properties of MDGI may relate to its ability to inhibit cell growth in vitro and to regulate other cellular functions.
TL;DR: Electrical stimulation of the posterior cricoarytenoid muscle, synchronized with inspiration, was achieved in dogs utilizing a radio frequency stimulus triggered by a chest wall expansion transducer, and it is felt that the system may be suitable for pacing the paralyzed human larynx.
Abstract: Electrical stimulation of the posterior cricoarytenoid muscle, synchronized with inspiration, was achieved in dogs utilizing a radio frequency stimulus triggered by a chest wall expansion transducer. This system brings about abduction of the paralyzed vocal cord for the entire duration of inspiration, which allows a normal flow of air through the larynx. The implantable part of that system was tested successfully in chronic experiments (up to 11 months) in dogs with experimental paralysis of the recurrent laryngeal nerve. We feel that the system may be suitable for pacing the paralyzed human larynx.
TL;DR: In this article, a fluoride-sensitive membrane for ion-sensitive field effect transistors was constructed by vapour deposition of LaF3 and high frequency C-V measurements were carried out on the system semiconductor/insulator/LaF3/electrolyte.
TL;DR: The plasmid content and toxicity of nine different strains of Microcystis aeruginosa have been analyzed in this paper, and two different plasmids of 2.9 kb and 8.5 kb were detected.
Abstract: The plasmid content and toxicity of nine different strains ofMicrocystis aeruginosa have been analyzed. The two toxic strains of the HUB Culture Collection were found to carry each two plasmids, pMA1 and pMA2, of 2.9 kb and 8.5 kb, respectively. In strains PCC 7813 and PCC 7820, also toxic, two different plasmids of 2.6 kb and 16 kb were detected. Hybridization experiments showed that there exists no sequence homology between the pMA plasmids and the plasmids found in the PCC strains; but the pMA plasmids hybridized to chromosomal DNA of the toxic strains PCC 7820, PCC 7813, HUB 063, and the nontoxic strain HUB 5-3. In nontoxic strains no or at most one plasmid of unstable occurrence could be detected. Only one of the toxic strains investigated, SAG 14.85 (NRC-1), contained no plasmid.
TL;DR: In this paper, the thermodynamic functions for the nonideal xenon plasma are constructed by using recent Pade approximations for the Coulombic contribution and hard core, Van der Waals and polarisation approximation for the atomic contribution.
Abstract: By using recent Pade approximations for the Coulombic contribution and hard-core, Van der Waals and polarisation approximations for the atomic contribution, the thermodynamic functions for the nonideal xenon plasma are constructed. These formulae cover a large range of pressure and temperature. Single ionisation is studied by minimising the free energy with respect to the particle numbers. A second critical point is predicted. The coexistence line for the corresponding first order phase transition (weakly ionised plasma - strongly ionised plasma), the lines indicating the soft transition to a higher degree of ionisation at overcritical temperatures, as well as the border of the coexistence area are presented. The influence of the different interactions on the critical data is discussed.
TL;DR: In this paper, the effect of free-carrier screening on the absorption and refraction in the vicinity of the band-gap at room temperature was investigated on a 1μm slab.
Abstract: We report on large optical nonlinearities due to specific many-body effects in high-density electron-hole pair systems. On bulk CdS we study the effect of free-carrier screening on the absorption and refraction in the vicinity of the band-gap at room temperature. Steady-state saturable absorption at mW-power levels and four-wave mixing with first-order efficiencies as large as 2% of the incoming light are demonstrated on a 1μm slab. On CuBr microcrystallites embedded in glass we investigate the changes of the exciton absorption caused by many-exciton effects both at cryo and room temperature. In contrast to bulk semiconductors, we observe a blue shift of the exciton peak at resonant optical excitation. In addition, strong saturation of absorption with very large contrast shows up. We find Lorentzian saturation intensities in the 100 kW/cm2 range.
TL;DR: The data suggest that subcellular compartmentation and/or intracellular transfer of PC destined to storage in lamellar bodies, but not secretion of lamellars bodies, involves an enrichment of dipalmitoyl-PC and a depletion of 1-palmitoysl-2-oleoyL-PC.
Abstract: It is not yet completely understood how a cell is able to export specific phospholipids, like dipalmitoylphosphatidylcholine (dipalmitoyl-PC), which is secreted by pneumocytes type II, into pulmonary surfactant. The acyl species composition of [3H]PC which was synthesized in type II cells in the presence of [2-3H]glycerol resembled the species composition of PC localized in intracellular pneumocyte membranes. This species pattern was different from the pattern of PC of lamellar bodies, i.e., intracellularly stored surfactant, by a higher proportion of dipalmitoyl-PC mainly at expense of 1-palmitoyl-2-oleoyl-PC. Lamellar body PC in turn showed the same species distribution as surfactant PC. The data suggest that subcellular compartmentation and/or intracellular transfer of PC destined to storage in lamellar bodies, but not secretion of lamellar bodies, involves an enrichment of dipalmitoyl-PC and a depletion of 1-palmitoyl-2-oleoyl-PC. In contrast, the acyl species pattern of phosphatidylglycerol does not seem to undergo gross changes on the path from synthesis to secretion.
TL;DR: In this paper, a stochastic theory is presented for nucleation and growth of clusters in a finite system, where the cluster growth and shrinkage occurs by the attachment/evaporation of free particles.
Abstract: A stochastic theory is presented for nucleation and growth of clusters in a finite system. We consider a discrete cluster distribution for which the free energy and the equilibrium probability distribution are derived. The cluster growth and shrinkage occurs by the attachment/evaporation of free particles. The transition probabilities reflect that clusters of different sizes cannot evolve independently due to the limitation of the total particle number and the finite system size. Computer simulations demonstrate the time dependence of various significant properties of the system: e.g. cluster distribution, supersaturation, critical cluster size. We discuss three stages of the phase transition in finite systems: a short period of predominant nucleation, a period of growth of supercritical clusters and a period of Ostwald ripening. A Fokker-Planck equation for the mean cluster distribution is derived and solved by means of computer simulations. The evolution of the mean cluster distribution can be described by two time scales which are determined by simulation experiments.
01 Jun 1988
TL;DR: In this paper, it was shown that timed Petri nets under the earliest firing rule can be transformed equivalently to Petri networks working under the maximum firing strategy, and two sufficient conditions for live Petri net to remain live under any timing.
Abstract: We show that timed nets under the earliest firing rule can be transformed equivalently to Petri nets working under the maximum firing strategy. Additionally, we give two sufficient conditions for live Petri nets to remain live under any timing.
TL;DR: Thermitase, the thermostable alkaline protease from Thermoactinomyces vulgaris, has been crystallised in a 1:1 complex with eglin, the inhibitor from the medical leech, using the subtilisin Carlsberg‐eglin structure as a model.
TL;DR: In this paper, a variete de spin de Kahler fermee de Courbure scalaire positive R pour laquelle (R 0 /3) 1/2 (r 0 =min(R)) est une valeur propre de l'operateur de Dirac.
Abstract: Si M 6 est une variete de spin de Kahler fermee de courbure scalaire positive R pour laquelle (R 0 /3) 1/2 (R 0 =min(R)) est une valeur propre de l'operateur de Dirac, alors M 6 est analytiquement isometrique soit a l'espace projectif P 3 (C) soit a la variete drapeau F(C 3 ) par rapport a leurs structures de Kahler naturelles
TL;DR: The Cole-Vishkin technique of deterministic coin tossing is applied to the computation of independent sets in trees and graphs of bounded degree and how to update minimum spanning trees efficiently in parallel is shown.
TL;DR: In this paper, a model of nonstochiometry and defect structure in PbTe is proposed, where the disorder takes place mainly in the Pb sublattice.
Abstract: The nostoichiometry and point-defect structure of PbTe was investigated by various methods including carrier-concentration, lattice-constant, positron-annihilation and vapour-density measurements. The results are discussed in comparison with data published by other authors. New aspects are obtained especially from high-temperature experiments. A model of nonstoichiometry and defect structure in PbTe is proposed. The stability region of PbTe is essentially broader than reported until now. The disorder takes place mainly in the Pb sublattice, i.e., there occur charged Pb vacancies (Te-rich) and Pb interstitials (Pb-rich), respectively, as well as probably additional neutral Pb interstitials in Pb-rich PbTe.
Die Nichtstochiometrie und Punktdefektstruktur von PbTe wurde mit verschiedenen Methoden untersucht, u. a. durch Messungen der Ladungstragerkonzentration, der Gitterkonstante, der Positronenannihilation sowie der Dampfdichte. Die Ergebnisse werden mit denen anderer Autoren verglichen. Neue Aspekte ergeben sich insbesondere aus Hochtemperaturmessungen. Ein Modell der Nichtstochiometrie und der Defektstruktur in PbTe wird vorgeschlagen. Das Stabilitatsgebiet von PbTe ist wesentlich breiter als bisher berichtet. Die Fehlordnung tritt hauptsachlich im Pb-Untergitter auf, d. h., es existieren geladene Pb-Leerstellen (Te-reich) bzw. Pb-Zwischengitterionen (Pb-reich) sowie zusatzlich wahrscheinlich neutrale Pb-Zwischengitteratome in Pb-reichem PbTe.
01 Jan 1988
TL;DR: Poly(ethylene glycol) (PEG) has met wide applications in biology and medicine, PEG is used as a fractional precipitating agent for protein purification and isolation, DNA and protein crystallization and for the cryo preservation of biological material.
Abstract: Poly(ethylene glycol) (PEG) has met wide applications in biology and medicine, PEG is used as a fractional precipitating agent for protein purification and isolation, DNA and protein crystallization and for the cryo preservation of biological material. PEG of a molecular weight of about 6000 is commonly used to induce fusion of liposomes as well as of a wide variety of plant protoplasts and animal cells.
TL;DR: Although primary hybridomas could be established from fusions with bone marrow-derived cells, only in nine out of 1616 initially seeded wells was Ig production registered, and higher yields of growing and human Ig-producing hybridoma lines were found when lymphocytes from spleen or lymph node were fused.
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