Phosphatidylserine counteracts physiological and pharmacological suppression of humoral immune response

1990

Phosphatidylserine (PS) is a necessary cofactor for protein kinase C (PKC) activation, and changes in the synthesis of PS have been shown to participate in the mechanism(s) involved in the transmembrane signaling of interleukin 1 (IL-1). In view of the age-associated defects in T-cell functions, in the present study we have addressed the question of whether an in vivo treatment with PS might interfere with such processes. Furthermore, the effect of an in vitro treatment with PS in human peripheral blood monocytes (PBMC) or splenocytes activated with a lectin mitogen, on the expression of IL-2 receptor, was assessed. While the process of ageing was accompanied by a marked decline of humoral …

Magnetic exchange interactions in the heteropoly complexes [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)]

1990

The magnetic properties of the heteropolyanions [M4(H2O)2(PW9O34)2]10− [M=Co(II) and Cu(II)] down to 4 K are reported. Their individual heteropoly molecules contain a rhomblike arrangement formed by four coplanar MO6 octahedra sharing edges. The magnetic properties support an intramolecular ferromagnetic exchange in the Co(II) tetramer, and antiferromagnetic exchange in the Cu(II) tetramer. These behaviors are discussed assuming anisotropic exchange in the Co(II) compound, and Heisenberg exchange in the Cu(II) compound. Carlos.Gomez@uv.es

Polycondensed nitrogen heterocycles. Part 23. Pyrrolo[3,2-c]cinnolines by a japp-klingemann type reaction

1990

Pyrrolo[3,2-c]cinnoline derivatives were obtained by an unusual Japp-Klingemann reaction involving an intramolecular azadehalogenation on the pyrrole nucleus. Such an azadehalogenation represents the first example of Japp-Klingemann reaction in which the extrusion of positive chlorine ion is verified.

Studies on the induction of gene mutations in bacterial and mammalian cells by the ring-opened benzene metabolites trans,trans-muconaldehyde and tran…

1990

t,t-Muconaldehyde and t,t-muconic acid have been investigated for the induction of gene mutations in Salmonella typhimurium (reversion of the his- strains TA97, TA98, TA100, TA102, TA104 and TA1535), Escherichia coli (reversion of the trp- strain WP2 uvrA) and Chinese hamster V79 cells (acquisition of resistance toward 6-thioguanine). t,t-Muconaldehyde proved weakly mutagenic in strain TA104 in the presence and absence of NADPH-fortified postmitochondrial fraction from rat liver homogenate (S9 mix). In strains TA97, TA100 and TA102, weak positive responses were observed only in the presence of S9 mix. In strains TA98, TA1535 and WP2 uvrA, the result was negative. In V79 cells, the mutation …

Hydrodynamic chromatography of macromolecules on small spherical non-porous silica particles

1990

Abstract Non-porous silica spheres with sizes in the range 1.4–2.7 μm were applied as packings for the hydrodynamic chromatography (HDC) of macromolecules. Highly efficient columns, with a reduced plate height below 2, were packed with these small particles. Up to molecular weights of 10 6 the elution behaviour of polystyrenes agreed very well with existing theoretical models. However, for larger polystyrenes the flow-rate exerted an influence on the relative peak positions. The applicability of HDC to rapid separations of soluble macromolecules and inorganic colloids was demonstrated.

T-odd and CP-odd triple momentum correlations in the exclusive semi-leptonic bottom meson decay

1990

Abstract We study T-odd triple momentum correlations in exclusive semi-leptonic (S l ) bottom meson decays B → D ∗ (→ D π)+ l +ν l . We define asymmetry ratios that measure these T-odd triple momentum correlation effects. We provide a careful discussion of possible unitarity contributions to the asymmetry ratios. The conclusion is that strong interaction unitarity contributions are small or, in the case of one particular T-odd observable, absent. CP-violating contributions to the asymmetry ratios would have to come from new non-standard sources as there are no standard model contributions. Possible new CP-violating contributions are parametrized in terms of an effective four-fermion hamilto…

Crystal structure and magnetism of Co(HPO3)⋅H2O : A novel layered compound of Co(II)

1990

Under the terms of the Creative Commons Attribution (CC BY) license to their work.-- et al.

A Dido problem for domains in ?2 with a given inradius

1990

We find which are the simply connected domains in ℝ2 satisfying the Dido condition for a straight shoreline, with a given area A and a fixed inradius ϱ, which minimize the length of the free boundary. There are three different cases according to the values of A and ϱ.

Binding of Tat Protein to TAR Region of Human Immunodeficiency Virus Type 1 Blocks TAR-Mediated Activation of (2′-5′)Oligoadenylate Synthetase

1990

The TAR sequence of the 5' leader of HIV-1 long terminal repeat-directed mRNA was found to be able to bind to and to activate double-stranded RNA-dependent (2'-5')A synthetase. Binding of TAR to the purified synthetase in vitro was abolished by addition of HIV-1 Tat protein, which binds to this sequence with a high affinity. Inhibition of TAR-mediated activation of (2'-5')A synthetase by Tat was prevented in the presence of the Zn2+ and Cd2+ chelators o-phenanthroline and penicillamine, which did not impair TAR-synthetase interaction. Transient expression assays of bacterial chloramphenicol acetyltransferase (CAT) gene in HeLa cells revealed that the levels of both CAT mRNA and CAT protein …

Azide and chloride binding to carboxypeptidase A in the presence of L-phenylalanine

1990

The interaction of chloride with native and cobalt (Co)-substituted carboxypeptidase-A (CPD) has been investigated by 35Cl nuclear magnetic resonance (NMR) spectroscopy in the presence and absence of L-Phe. The affinity constants of azide and chloride toward the Co(II)CPD·L-Phe complex have been measured by electronic spectroscopy. The correlation times determining T1 and T2 for the 35Cl nuclei are related to movements inside the cavity. In the presence of L-Phe, the anions bind to the metal with a relatively high affinity at pH values below 6. Anion binding to the Co enzyme can be analyzed in terms of the three protonation state model for the enzyme (EH2 α EH α E). In the presence of L-Phe…

Comparison of selective internal iliac pharmaco-angiography, penile brachial index and duplex sonography with pulsed Doppler analysis for the evaluat…

1990

AbstractBetween July 1987 and February 1988 selective internal iliac angiography was performed before and after intracavernous injection of papaverine plus phentolamine in 43 patients with erectile dysfunction. In 63% of the patients stenosis or occlusion of the pudendal artery was found. The penile brachial index was calculated and duplex sonography with pulsed Doppler analysis was performed in 23 patients. Angiography and penile brachial index correlated in only 39% of the patients, whereas selective internal iliac angiography and duplex sonography correlated in 91% (21 of 23). In 2 patients duplex sonography with pulsed Doppler analysis rendered better information about penile arterial p…

IN SITU HYBRIDIZATION FOR DETECTION OF HEPATITIS B VIRUS GENOMES IN LIVER TISSUE OF CHRONIC INFECTED CHILDREN

1990

Detection of hepatitis B virus (HBV)-DNA in the liver of chronic infected patients is presently the most sensitive marker of viral replication and infectivity. In situ hybridization (ISH) allows the direct visualization of HBV infected liver cells and distribution of the viral sequences. This study was done to establish ISH and correlate the findings with conventional markers for HBV infection. Methods. Liver biopsies of 50 patients (28 ♂, 22 ♀) aged 0.5-20 years (mean 10.3) with various histological diagnoses were tested by 1SH. The HBV-DNA probe was labeled by nick translation with 35S-CTP to a specific activity of 3-5×108 cpm/μg DNA. Results. HBV-DNA/mRNA could be demonstrated in 38 pati…

Notiz �ber Injektoren

1990

Effect of Phosphinothricin (Glufosinate) on Photosynthesis and Photorespiration

1990

Phosphinothricin (PPT) causes a rapid inhibition of photosynthesis under atmospheric conditions (400 ppm CO2, 21% O2). However, under conditions (1000 ppm CO2, 2% O2) under which photorespiration cannot occur, there is no or only a very low rate of photosynthesis inhibition by phosphinothricin. Under both conditions, a strong NH4 +-accumulation is apparent caused through the inhibition of glutamine synthetase by phosphinothricin. This indicates, that NH4 +-accumulation cannot be the primary cause for photosynthesis inhibition by phosphinothricin, but a process in connexion with photorespiration plays a central role. Through the lack of amino donors, the transamination of glyoxylate to glyci…

Mixed‐valence trinuclear manganese clusters : Influence of the electronic transfer on the magnetic properties

1990

The magnetic behavior of mixed‐valence trinuclear clusters d4‐d4‐d5 is discussed on the basis of a model which takes into account valence delocalization and Heisenberg exchange. This model considers the competing effect between the electronic transfer and the localization of the extra electron due to an asymmetry of the triangular entity. The magnetic properties of the mixed‐valence oxo‐centered Mn(II)‐Mn(III)‐Mn(III) complexes formulated as Mn3O(O2CR)6L3 (R=Me, L=pyridine) are discussed on the basis of the developed model, supporting a significant intramolecular electron transfer. A comparison of these results to those previously reported by assuming a valence‐trapped model is given. Carlo…

The ferrimagnetic compounds CoM[M’(EDTA)]2⋅4H2O(M,M’=Co,Ni): Magnetic characterization of CoCo[Ni(EDTA)2]⋅4H2O

1990

Under the terms of the Creative Commons Attribution (CC BY) license to their work.

Giant liposomes as model membranes for immunological studies: spontaneous insertion of purified K1-antigen (poly-alpha-2,8-NeuAc) of Escherichia coli.

1990

A flow chamber has been constructed to use giant liposomes (diameter 5-50 microns) as model membranes for immunological studies and other experiments involving the interaction with water-soluble compounds. As an example of immunological importance, the insertion of purified K-antigen from Escherichia coli K1 has been studied. Despite its large hydrophilic part (poly-alpha-2,8-NeuAc), which is capped at its potential reducing end with phosphatidic acid acting as a lipid anchor group, this water-soluble material is readily incorporated into liposomal membranes of dimyristoylphosphatidylcholine (DMPC). The incorporation has been proven by immunofluorescence using a FITC-labeled monoclonal anti…

Hydrolytic action of phospholipase A2 in monolayers in the phase transition region: direct observation of enzyme domain formation using fluorescence …

1990

Phospholipase A2, a ubiquitous lipolytic enzyme highly active in the hydrolysis of organized phospholipid substrates, has been characterized optically in its action against a variety of phospholipid monolayers using fluorescence microscopy. By labeling the enzyme with a fluorescent marker and introducing it into the subphase of a Langmuir film balance, the hydrolysis of lipid monolayers in their liquid-solid phase transition region could be directly observed with the assistance of an epifluorescence microscope. Visual observation of hydrolysis of different phospholipid monolayers in the phase transition region in real-time could differentiate various mechanisms of hydrolytic action against …

El farmacèutic català creador de cultura.

1990

Es tracta d'un estudi aprofundit de l'obra literària de ficció de deu farmacèutics escriptors catalans del segle XX. Dins la història de la Farmàcia és un treball de tema original i inèdit que suposa un llegat bibliogràfic important d'especial interès per als Farmacèutics i també, àdhuc, per als estudiosos de les Lletres Catalanes. S'ha aconseguit un treball de notable interès per al foment i la difusió de la cultura de la classe farmacèutica. S'hi estudien de forma exhaustiva aquests personatges contemporanis concretament: llur personalitat, aspiracions i llur obra. La metodologia ha consistit a analitzar de forma detallada llur vida acadèmica i professional, els premis literaris rebuts, e…

Measurement of the rate of the decay KL→e+e−γ and observation of a form factor in this decay

1990

Abstract A large sample of Dalitz decays, K L → e + e − γ , has been observed. The branching ratio is Γ(K L →e + e − γ) Γ(K L → all )=(9.2±0.5±0.5)×10 −6 in good agreement with theoretical predictions. We observe an enhancement at high masses in the distribution of the invariant electron-positron pair mass, compared to the distribution expected from QED. This excess is interpreted as being due to virtual mesons contributing to the photon propagator.

Monte Carlo study of the order-parameter distribution in the four-dimensional Ising spin glass

1990

We investigate the order-parameter distribution P(q) of the Ising spin glass with nearest-neighbor interactions in four dimensions using Monte Carlo simulations on lattices of linear dimension up to L=6. We find that, below the transition temperature ${\mathit{T}}_{\mathit{c}}$, the weight at small q seems to saturate to a nonzero value as the size increases, similar to the infinite-range Sherrington-Kirkpatrick model. We discuss our results in the light of recent theoretical predictions for the nature of the spin-glass phase.

Pair production of helicity-flipped neutrinos in supernovae.

1990

The emissivity was calculated for the pair production of helicity-flipped neutrinos, in a way that can be used in supernova calculations. Also presented are simple estimates which show that such process can act as an efficient energy-loss mechanism in the shocked supernova core, and this fact is used to extract neutrino mass limits from SN 1987A neutrino observations.

Enhanced expression of the proto-oncogenes fos and raf in the rhabdomyosarcoma cell line BA-HAN-1C after differentiation induction with retinoic acid…

1990

BA-HAN-IC is a clonal rat rhabdomyosarcoma cell line consisting of proliferating mononuclear tumor cells, some of which spontaneously fuse to form terminally differentiated post-mitotic myotubes. Exposure of BA-HAN-IC cells to retinoic acid (RA) or N-methylformamide (NMF) resulted in a significant inhibition of proliferation (p less than 0.001) and in cellular differentiation, as evidenced by a significant increase in the creatine kinase (CK) activity (p less than 0.05) and the number of terminally differentiated post-mitotic myotubes (p less than 0.001). Furthermore, between 5% (NMF) and 30% (RA) of the mononuclear tumor cells exhibited ultrastructural features of rhabdomyogenic differenti…

Morphogenesis of the wing Anlagen in the mealworm beetle tenebrio molitor during the last larval instar.

1990

The wing Anlagen of Tenebrio develop from epidermal cells located on the lateral margins of meso- and metathoraces. Three to four days after larval ecdysis, these cells start to proliferate slowly, continuing to do so until day 13 which corresponds to the period of the pupal commitment of the remaining epidermis. The wing Anlagen cells then proliferate rapidly until day 18.5. Three days before pupal ecdysis, the mitotic index falls suddenly while 40% of the Anlagen cells disappear owing to cell degeneration. The sudden changes observed in the mitotic index are correlated with two hemolymphatic peaks in ecdysteroid levels. Anlagen of the forewings and hindwings show similar development excep…

ChemInform Abstract: Convenient and Optimized Procedure for the Syntheses of Di- and Trialkoxycarbenium Tetrafluoroborates.

1990

Abstract A convenient and optimized procedure for the synthesis of some diand trialkoxycarbenium tetrafluoroborates under an argon atmosphere and using a specially developed apparatus is described.

Dual effect of 1-deoxymannojirimycin on the mannose uptake and on the N-glycan processing of the human colon cancer cell line HT-29.

1990

International audience; 1-Deoxymannojirimycin (dMM), a specific alpha-mannosidase I inhibitor, completely blocks the conversion of Man9-8GlcNAc2 into Man7-5-GlcNAc2 in both differentiated and undifferentiated human adenocarcinoma HT-29 cells. Besides this well known effect on N-glycan trimming, we describe here a novel effect of this inhibitor on the D-[2-3H]mannose uptake that is exclusively observed in differentiated intestinal cells, i.e. cells that display a functional apical brush border membrane. This inhibition of D-[2-3H]mannose uptake was shown to be dose-dependent and reversible. Moreover, using microsomal fractions we showed that this effect depends only on the integrity of the b…

Veltījums Latvijas Jaunatnes teātra ansamblim [dzejolis]

1990

Poetry by Latvian biologist, orchid researcher Ernesto Foldats is dedicated to the ensemble of the Latvian Youth Theater. Typewritten on 4 pages. Stored in the Museum of the University of Latvia Botanical and Mycological collections.

Ultrastable Holographic Cyclic Interferometer

1990

ABSTRACT We propose to use an off-axis zone plate, as beam splitter and as beam recombiner, to set a cyclic interferometer. We show that this optical device can be tuned to generate, with high stability, cosinusoidal gratings and/or cosinusoidal zone plates. 1. INTRODUCTION Several modern optical devices incorporate holographically generated optical elements; either for substituting conventional optical elements, or for introducing novel techniques for manipulating light.In particular, in the field of interferometry there are attemps to use diffracting ele­ ments for testing large optics; without using large beam splitters1"^.The aim of this work is to suggest, and to experimentally verify,…

ChemInform Abstract: Photochemistry of 7-Acetoxybenzopyran Derivatives. Synthesis of Eupatoriochromene and Encecalin.

1990

Abstract The photolysis of the 7-acetoxybenzopyran derivatives 1a-5a has been carried out. Chromene 1a was found to undergo extensive photopolymerization. Chromanone 2a underwent a rather inefficient photo-Fries rearrangement to the 6 - and 8 - acetyl derivatives 2b and 2c . Diacetoxychromene 3a gave the unsaturated ketone 8 as the main product, besides its deacetylation analogue 9 and chromanone 11 . Diacetoxychroman 4a afforded a mixture of four C-acetyl products: 1b, 1c, 2b and 2c , together with Chromene 1a and chromanone 2a. Finally, irradiation of chroman 5a gave rise to a mixture of the two possible photo-Fries products 5b (43%) and 5c (52%). The mechanistic implications of the above…

Bidirectional Nonorthogonal Schardin-Lau Interferometer

1990

We discuss the formation of self-images of a 2-D grating composed by two rulings of equal period, but in-plane rotated. We describe the in-register condition for setting the lensless Lau effect, with this type of gratings; and we propose to use the above configuration for interferometrically visualizing, in noncoherent light, phase structures, in two nonorthogonal directions.

ChemInform Abstract: Cycloaddition Reactions of 1-tert.-Butyl-4-vinylpyrazole.

1990

1-tert-Butyl-4-vinylpyrazole1 a reacts with dimethyl acetylenedicarboxylate (DMAD), methyl propiolate (MP) and N-phenylmaleimide (NPMI) affording the indazole derivatives2,3, and5 as a result of a Diels-Alder ([4 + 2]) cycloaddition. With diethylazodicarboxylate (DEAZD), tetracyanoethylene (TCNE) and 4-phenyl-1,2,4-triazole-3,5-dione (PTAD) the reaction takes place exclusively through the olefinic substituent and the adducts6,7, and9 were isolated. The alkenylpyrazoles1 b–d reacted withDMAD and N-phenylmaleimide to give polymers.

ChemInform Abstract: Aryl Radicals by Copper(II) Oxidation of Hydrazines: A New Method for the Oxidative and Reductive Arylation of Alkenes.

1990

Abstract A new source of aryl radicals interesting from the preparative point of view has been found in the reaction of arylhydrazines and copper(II) sulfate. The process allows selectively both the reductive and oxidative arylation of alkenes.

Some comments on the history of thermogravimetry

1990

Abstract In a review of the authors about the history of vacuum microbalance techniques (including a chronology in table form), also published in Thermochimica Acta, (ref. 1) it uas pointed out, that also some corrections are to be made on the history of therinogravimetry. The first findings of balances are dated to about 3000 B.C. A gravimetric hygrometer is mentioned by Nicolaus Cusanus in 1450. In the 19th century chemical reactions at variable temperatures uere investigated using balances. The very beginning of the thermogravinietry is antedated to the work of Talabot who in 1833 at Lyon equipped a laboratory with thermobalances for quality control of Chinese silk.

Neonatal form of nemaline myopathy, muscle immaturity, and a microvascular injury.

1990

An infant with a neonatal form of nemaline myopathy showed ultrastructural features of muscle immaturity. Immaturity was characterized by an abnormal presence of myotubes, as well as cells in clusters within a common basement membrane and a great number of satellite cells adhering to very small muscle fibers. In addition, degenerative changes and a severe microvascular lesion were observed. The pathologic findings in the muscle of this patient were those of neonatal nemaline myopathy complicating severe microvascular injury, possibly induced by an unknown toxic agent. ( J Child Neurol 1990;5:122-126).

Multiple vibrational resonances in the Raman spectra of liquid ethanes

1990

The Raman spectra of liquid ethane, ethane-d3 and ethane-d6 were recorded and analysed. The CH3 and CD3 stretching regions were computer resolved using Cauchy-Gaussian and Voigt functions to account for asymmetric band shapes. Multiple vibrational resonances were investigated using the wavenumbers and observed intensities in these regions. The developed basis functions show strong mixing of the levels in these regions. In general the resonances appear to be less strong in the liquid phase than reported in previous studies of the gaseous state. Some new assignments in the liquid-state spectra of ethanes could be suggested.

Classical thermodynamics of the Heisenberg chain in a field by generalized Bethe ansatz method

1990

Abstract Using the classical action-angle variables for the continuous model, we study the thermodynamics of the classical Heisenberg chain in an applied field by a generalized Bethe ansatz approach. The crucial point consists in the derivation of a phase-shifted density of states for the excitations of the model, obtained by imposing periodic boundary conditions. In the thermodynamic limit, the free energy can be expressed in terms of the solution of a non-linear integral equation, showing the universal dependece of the variable x=(JH) 1 2 /T .