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At least 793 records · Page 44Linked to original sources
PubMed1985

Synthesis and biological evaluation of the superagonist [N alpha-chlorotriazinylaminofluorescein-Ser1,Nle4,D-Phe7]-al pha-MSH.

The fluorescein-labeled melanotropin [N alpha-chlorotriazinylaminofluorescein-Ser1,Nle4,D-Phe 7]-alpha-MSH, was prepared by solid-phase techniques of peptide synthesis. The biological actions of this analogue were determined in several melanocyte bioassays and were compared with the parent peptide [Nle4,D-Phe7]-alpha-MSH and the native hormone alpha-MSH. The fluorescein compound was a superpotent agonist with approximately 10 times more activity than alpha-MSH in both the frog and the lizard skin bioassays. Murine S91 melanoma cells assayed in vitro (tyrosinase bioassay) were as responsive to the fluorescein analogue as to alpha-MSH. The analogue exhibited ultraprolonged biological activity and the biological activities were unaffected by treatment of the analogue with alpha-chymotrypsin. The fluorescein-labeled melanotropin should prove useful for melanotropin receptor characterization.

Animals↗
PubMed2005

Characterization and properties of G4X mutants of Ralstonia eutropha PHA synthase for poly(3-hydroxybutyrate) biosynthesis in Escherichia coli.

Modification of the type I polyhydroxyalkanoate synthase of Ralstonia eutropha (PhaC(Re)) was performed through systematic in vitro evolution in order to obtain improved PhaC(Re) having an enhanced activity of poly(3-hydroxybutyrate) (PHB) synthesis in recombinant Escherichia coli. For the first time, a beneficial G4D N-terminal mutation important for the enhancement of both PHB content in dry cells and PhaC(Re) level in vivo was identified. Site-directed saturation mutagenesis at the G4 position enabled us to identify other mutations conferring similar enhanced characteristics. In addition, the PHB homopolymer synthesized by most G4X single mutants also had higher molecular weights than that of the wild-type. In vitro enzymatic assays of purified G4D mutant PhaC(Re) revealed that the mutant enzyme exhibited slightly lower activity and reaction efficiency compared to the wild-type enzyme. [diagram in text].

Acyltransferases↗
PubMed1991

Demonstration of projections from the lateral nucleus to the basal nucleus of the amygdala: a PHA-L study in the monkey.

Previous studies of the intrinsic connections of the amygdaloid complex in the rat, cat and monkey demonstrated that the lateral nucleus projects prominently to the accessory basal nucleus and periamygdaloid cortex and lightly to several other nuclei of the amygdala. Most previous studies have emphasized the lack of a connection between the lateral and basal nuclei. As part of ongoing studies of the intrinsic circuitry of the monkey amygdala, we have placed discrete, iontophoretic injections of the lectin anterograde tracer Phaseolus vulgaris leucoagglutinin into the lateral nucleus of the Macaca fascicularis monkey. In addition to confirming the well established intrinsic connections of the lateral nucleus, heavy fiber and terminal labeling was also observed in the adjacent basal nucleus. The projection innervated all divisions of the basal nucleus and tended to be somewhat denser rostral to the level of the injection site. This hitherto unreported intrinsic connection provides a means by which the lateral nucleus, which is the principal recipient of afferents from sensory neocortex, can influence cells of the basal nucleus, which originate the major amygdalofugal projection to the neocortex.

Amygdala↗
PubMed1988

Organization of feedback and feedforward projections of the barrel cortex: a PHA-L study in the mouse.

In order to analyze the organization of the efferent projections of single barrel columns (BC, i.e. a barrel in layer IV of parietal cortex plus the cortical tissue above and below it), we made small iontophoretic injections of the anterograde tracer Phaseolus vulgaris leucoagglutinin in the barrel cortex of 20 adult mice. On the basis of reconstructions of the sites of terminal labelling, the brain regions receiving projections from the barrel cortex could be identified and classified in five groups. Each group is characterized by the topography of the distribution of efferents arising from a single BC. The projections to the trigeminal sensory complex are point to point: i.e. one BC projects only to the site of termination of the primary sensory neurons innervating the corresponding whisker follicle. In the ventrobasal thalamic nucleus BC projections are not restricted to the corresponding barreloid; instead they contract parts of barreloids belonging to one arc. In the reticular and posterior thalamic nuclei the projections from a row of BC's converge to a collective termination site, whereas in the superior colliculus the projections from an arc of BC's converge to a common termination site. There is a complete overlap of BC projections in restricted zones within SII, motor cortex, perirhinal cortex, contralateral barrelfield, caudoputamen and pons. The organization of the efferents from the barrel cortex demonstrates a contrast between feedback and feedforward projections from this important area of neocortex.

Animals↗
PubMed1985

Impaired in vitro growth of PHA induced T lymphocyte colonies in hemodialyzed renal failure patients.

Using an in vitro method that allows the study of the colony forming capacity of phytohemagglutinin stimulated peripheral blood T lymphocytes, we have detected an impaired T cell colony formation in hemodialyzed renal failure patients. By contrast a near normal pattern of responses was observed in patients treated with a conservative therapy. The poor in vitro T cell responsiveness of hemodialyzed patients was not corrected by supplementing the cultures with an adherent cell contitioned medium prepared from normal donors. We conclude that an intrinsic defect of the T cell colony forming capacity exists in hemodialyzed patients.

Adult↗
PubMed1976

[Skin tests with phytohaemagglutinin (PHA). Correlation with other parameters of cell-mediated immunity (author's transl)].

100 healthy persons were investigated to find out whether there is a correlation between a lymphocyte stimulation (3H-thymidine incorporation in the lymphocyte transformation test) with phytohaemagglutinin, pokeweed mitogen and concanavalin A and the in vivo reactivity to intracutaneous phytohaemagglutinin application (measured as medium diameter of infiltrates). Further we searched for an influence of positive or negative reactivity to the specific antigens trichophytin, candidin and streptokinase-streptodornase. 1. There is a good qualitative correlation in normal persons between in vitro lymphocyte stimulation by phytohaemagglutinin, pokeweed mitogen and concanavalin A and the medium diameter of infiltrates after intracutaneous application of 2 mug phytohaemagglutinin. Using lower doses of phytohaemagglutinin no such correlation could be found. A quantitative correlation between the medium diameter of infiltrates and lymphocyte transformation by phytohaemagglutinin and pokeweed mitogen cannot be demonstrated. For concanavalin A there is a negative correlation significant at the 99% level. 2. In vivo reactivity to phytohaemagglutinin does not differ in persons with negative and positive reactions to the specific antigens. 3. Lymphocyte stimulation by phytohaemagglutinin, pokeweed mitogen and concanavalin A of persons with positive reactions to trichophytin, candidin and streptokinase-streptodornase is significantly greater than in those with negative reactivity. 4. The results indicate in vivo phytohaemagglutinin testing as a good screening method to judge cell-mediated immunocompetence. The general applicability for differentiation of immunodeficient and immunocompetent patients is to be further investigated.

Adolescent↗
PubMed1983

Inhibition and recovery of DNA synthesis in PHA-stimulated u.v.-irradiated lymphocytes from patients with actinic keratosis.

The recovery, after inhibition by u.v.-irradiation, of phytohaemagglutinin-stimulated DNA synthesis is impaired in lymphocytes from patients with multiple actinic keratoses (AK) compared to the recovery in lymphocytes from age-matched, control individuals. This shows that the reduced level (50%) of DNA repair activity in AK cells is sufficiently different from that in normal cells to significantly affect cellular activity.

DNA Repair↗