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  • 1985-1989  (64)
Collection
Year
  • 1
    Electronic Resource
    Electronic Resource
    Springer
    Archives of microbiology 140 (1985), S. 343-346 
    ISSN: 1432-072X
    Keywords: Escherichia coli ; Colicin M ; Functional domains ; Aminoterminal sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract The structure of colicin M of Escherichia coli was studied with regard to its organization into functional domains. A proteolytic fragment with an Mr of 24,000 was isolated which comprised the carboxyterminal portion of the protein. It adsorbed to the outer membrane receptor protein and inhibited killing of cells by colicin M and by phage T5 that uses the same receptor. The fragment killed cells when the outer membrane was rendered permeable to macromolecules for a short time by the osmotic shock procedure. It is concluded that the fragment contains the receptor binding site and the active center but is lacking the sequence required for transport into cells. The carboxy-terminal amino acid sequence-Lys-Arg of the fragment was identical to that obtained from colicin M. Release of lysine and arginine led to inactivation of colicin M. The sequence of the first 39 amino acids of the amino terminal end of colicin M was determined.
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-8798
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary SCC, ADV-SCC, ADV-ADCC and ADV-LYST as well as ND50-titres of neutralizing serum antibodies were examined in 36 passively immune pigs, 25 of which were vaccinated at 3 weeks of age and partly revaccinated 3 weeks later. Twenty-five vaccinated animals and 8 non-immune control pigs were challenged with infectious ADV. Independent of the state of maternal immunity the cytotoxic response of the white blood cells from all the animals was low at WPP 3 but rose with increasing age. ADV-LYST occurred only in some of the animals. A single vaccination evoked no significant effect on our immune parameters, but revaccination led to higher ADV-LYST and ADV-ADCC. In pigs vaccinated at WPP3 the neutralizing serum titres decreased gradually, similar to unvaccinated animals, indicating that the antibodies were of maternal origin. However, after vaccination at WPP6, no further decline of ND50-titres could be detected, pointing to a limited antibody production. Animals vaccinated at WPP3 and revaccinated 3 weeks later showed a significant increase of serum neutralizing titres. Whereas the controls showed typical symptoms of Aujeszky's disease, the immune animals, especially the unvaccinated passively immune pigs, showed only elevated temperatures and most of them excreted small amounts of ADV. The development of cellular immunity after infection was rather similar within the maternally immune group independent whether the animals had been vaccinated or not, but ADV-ADCC and ADV-LYST showed a more rapid progress within the vaccinated group than in the non-vaccinated group and the non-immune control group. Infection resulted in significantly higher ND50 titres in vaccinated and revaccinated animals than in unvaccinated animals, indicating a secondary response in those pigs. Thus, ADV sensitization of lymphocytes had been evoked by vaccination despite the presence of maternal antibody. The interpretation of the results was complicated by great individual and litter-dependent variations of the immune parameters.
    Type of Medium: Electronic Resource
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  • 3
    ISSN: 1432-0584
    Keywords: ITP ; Pregnancy ; Hemostasis ; Bleeding time ; Therapy
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary ITP is a relatively common disorder seen in pregnancy. Current recommendations for management of patient with ITP recommend maintaining the platelet count above 50×109/L and the bleeding time less than 20 min. It has been well documented that the bleeding time in ITP is disproportionately shortened in many patients relative to the platelet count. We present a prospective study of 24 ITP patients in whom the bleeding time was used as an indicator for therapeutic intervention in pregnancy. Indications for therapy with prednisone and/or intravenous gammaglobulin were the following: significant clinical hemorrhage due to thrombocytopenia; bleeding time of greater than 20 min at the baseline platelet count; for normalization of hemostasis prior to delivery or surgical procedure. Caesarean section was performed only in cases in which there were obstetrical indications for this mode of delivery or when the fetal platelet count (obtained by fetal scalp vein sample) was less than 50×109/L. Of 24 patients with ITP, eight had significant thrombocytopenia (platelet count less than 50×109/L) throughout pregnancy. Only two patients required prolonged prednisone therapy. Both suffered side effects of chronic prednisone administration. Four patients were treated with prednisone for a short course (10–14 days) at term to improve hemostasis for delivery. One patient was treated with intravenous gammaglobulin at term in an effort to prevent severe neonatal thrombocytopenia. Seven patients required caesarean section; the remaining 17 patients underwent vaginal delivery. Only one minor bleeding complication was seen — a small wound hematoma post caesarean section. In summary, using the bleeding time as an indiator for therapeutic inervention, treatment of ITP in pregnancy can be minimized. Thus, therapy related toxicity can be avoided.
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  • 4
    ISSN: 1434-4475
    Keywords: S-Betaines ; Bis-trihaloacetyl-S-methylides ; Trifluoroacetyl-S-methylides ; 3-Chloro-1-chloroacetoxycarbonyl-2-oxo-1-tetrahydrothiophenium-1-yl-propanide ; X-ray structure
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Thetin (1) and the betain of-Thiolanyl-acetic acid,5 react with the anhydrides of trifluoroacetic acid (TFA) and trichloroacetic acid (TClA), respectively, to give stable diacyl-S-ylides2a,b and6a,b, respectively. In contrast to the corresponding N-betaines,1 and5 react with monochloroacetic anhydride (MClA) under formation of the diacyl-ylid2c from1, and the mixed anhydride of chloroacetic acid and chloroacetylthiolaniummethylid carboxylic acid9 from5. The formation of9 requires the establishment of an equilibrium between S-betain and S-ylid forms. An X-ray analysis has been performed on2a.
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  • 5
    ISSN: 1434-4475
    Keywords: Di-trifluoracetyl-N-ylide ; Benzyl-dimethylammonium- and phenyl-dimethylammonium-acetic acid betaine ; 1,3-Dimethylammonium-butyl acetic acid betaine ; 1,4-Dimethylpiperazinium acetic acid betaine
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract The influence of substituents at the ammonium nitrogen of acetic acid betaines on the reaction with trifluoracetic anhydride (TFA) has been investigated. Thus benzyl-dimethyl- and phenyl-dimethyl-betaines (1a, 1b) as well as the bifunctional betaines derived from 1,3-bis-(dimethylamino)-butane (5) or 1,4-dimethylpiperazine (7) may serve as examples. From these betaines, the symmetrical compound7 gives in 50% yield 1,4-dimethyl-piperazinium-ditrifluoracetyl-dimethylide (8), while the tendency of formation of the di-acyl-N-ylides2a, 2b, and6 is rather low.
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  • 6
    Electronic Resource
    Electronic Resource
    Springer
    Monatshefte für Chemie 118 (1987), S. 531-533 
    ISSN: 1434-4475
    Keywords: Trifluoromethane-sulfonic acid anhydride ; Tetrahydrothiopyranium-trifluoroacetyl-methylide ; Trimethylammonium-trifluoroacetyl-methylide ; 3,3,3-Trifluoro-2,2-bis(trifloxy)-1-tetrahydrothiopyranium-1-yl-propanide ; 3,3,3-Trifluoro-1-trimethylammonium-2,2-bis(trifloxy)-1-yl-propanide
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Tetrahydrothiopyranium-trifluoroacetyl-methylide (1) and trimethylammonium-trifluoroacetyl-methylide (2) give, in a surprising reaction, with trifluoromethane-sulfonic acid anhydride (3) the bis-trifluoromethane-sulfonate-ylides4 and5.
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  • 7
    ISSN: 1434-4475
    Keywords: 1,5-Bis-(4-nitrophenyl)-3-dimethylsulfonium-formazane tetra-fluoroborate ; 1,5-Bis-(4-nitrophenyl)-3-trimethylammonium-formazane tetra-fluoroborate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract Dimethylsulfonium acetic acid betaine (1) and thiolanium acetic acid betaine (4) react with 4-nitrophenyldiazonium tetrafluoroborate (2) in aceticacid solution to give the formazyl compounds3 and5. Reaction of dimethylsulfonium- and thiolanium-trifluoroacetyl-methylide (9 and11, resp.) with compound2 leads to the phenylhydrazones10 and13, whereas trimethylammonium-trifluoroacetyl-methylide (14) reacts with formation of the formazane derivative15.
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  • 8
    ISSN: 1434-4475
    Keywords: Tetrahydrothiopyranium acetic acid betain ; Mono- and diacyl-S-ylides ; 1,5-Bis (4-nitrophenyl)-3-tetrahydrothiopyranium formazane tetrafluoro-borate
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A comparative study has been performed on ethyl-methyl- and diethyl-mercaptoacetic acid (1 and2), and thianeaceticacid betain (3) with respect to their reactivity towards haloacetic acid anhydrides and 4-nitrobenzene-diazonium tetrafluoroborate. The results show that in analogy to related N-betaines the alkyl substituents at the cationic reaction center display a strong influence on reactivity. The most stable S-ylides are obtained from the cyclic S-betain3 in high yield. The1H-NMR spectra reveal that the protons of the methylene groups in compounds1–3 are fully exchanged for deuterium (in D2O) in contrast to the behavior of the corresponding N-betaines.
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  • 9
    ISSN: 1434-4475
    Keywords: Trimethylammonium acetic acid betaine ; Diethyl tartronate ; 1-Carbethoxy-2-methyl-(2,4-dinitrophenyl) osazone ; 1-Carbethoxy-(2,4-dinitrophenyl) osazone ; Glycolic acid nitrile
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Summary Diethyl bromomalonate and bromoacetonitrile, respectively, react with trimethylammonium acetic acid betaine in ethanol to give diethyl tartronate and glycolic acid nitrile, respectively. By analogy, ethyl α-chloroacetonate and ethyl bromopyruvate yield the respective hydroxy derivatives which were identified by their osazones2 and3. Under the same experimental conditions, mesoxalic acid and its dimethyl ester, respectively, are formed from dibromo malonic acid and its dimethyl ester and were characterized by their known hydrazones8 and9.
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  • 10
    ISSN: 1434-4475
    Keywords: Aniline ; Basicity ; Acylation ; Trimethylammonium-trifluoroacetyl-methylid ; Dimethylsulfonium-trifluoroacetylmethylid
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology
    Notes: Abstract A straight forward synthesis of trimethylammonium trifluoroacetyl methylide (2) starting from trimethylammonium-di-trifluoracetyl methylide (1) using aniline is described. Moreover, the nucleophilic reactivity of N- and S-Ylides with identical anionic component towards acetylating agents were studied with respect to the contribution of the cationic component.
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