Anti-phospholipase C antibodies inhibit the lectin-induced proliferation of human lymphocytes

A novel approach was used to assess the role of phosphoinositide hydrolysis in the mitogenic action of phytohemagglutinin (PHA) or concanavalin A (ConA). The treatment of human peripheral blood leukocytes (PBL) with monospecific antibodies against phospholipase C (PLC) produced a dose-dependent inhibition (up to 100%) of PHA (10 g/ml) or ConA (25 g/ml) proliferative effects. Thus, the activation of membrane-bound PLC is asine-qua-non condition for lectin-induced proliferation of T lymphocytes. The key-role of PLC versus protein kinase C (PKC) is stressed by the fact that the inhibition of PKC with Hidaka's compound H-7 (40 M) produced only a partial blockade (about 25%) of lectin mitogenic effect.To whom correspondence should be addressed.     

Changes in choline acetyltransferase activity and high-affinity choline uptake, but not in acetylcholinesterase activity and muscarinic cholinergic receptors, in rat somatosensory cortex after sciatic nerve injury

Selected cholinergic markers (choline acetyltransferase, acetylcholinesterase, muscarinic acetylcholine receptor, high-affinity choline uptake) were studied in the hindlimb representation areas of the rat somatosensory cortex and within the visual cortex 1 to 63 days after unilateral transection of the sciatic nerve. In the contralateral somatosensory cortex, peripheral deafferentation resulted in a significant reduction of choline acetyltransferase activity (by 15%) 3 days after sciatic nerve injury, and in a significant reduction of high-affinity choline uptake (by 30%) 1 day after nerve transection, in comparison to untreated control rats. Investigations in individual cortical layers revealed that the decrease of both choline acetyltransferase activity and high-affinity choline uptake sites was mainly due to reductions in cortical layer V. Acetylcholinesterase activity and [3H]quinuclidinyl benzilate binding to muscarinic acetylcholine receptors were not affected by unilateral transection of the sciatic nerve. In the ipsilateral somatosensory cortex, as well as in the visual cortex at both cortical hemispheres, no significant changes in the cholinergic parameters studied could be detected. The data indicate that peripheral deafferentation of the somatosensory cortex results in a transient change of presynaptic cholinergic parameters within the affected somatosensory area as early as 1 to 3 days after the lesion; thus, they emphasize the involvement of cholinergic mechanisms in cortical reorganizational events.     

Effects of an ACTH/MSH(4-9) analog (HOE 427) on the sleep EEG and nocturnal hormonal secretion in humans.

The synthetic ACTH/MSH(4-9) analog HOE 427 ("ebiratide"), which is behaviorally the most potent ACTH-derived peptide but which is devoid of endocrine activity, was administered intravenously in a pulsatile mode 4 times (120 micrograms each) at 2200, 2300, 2400 and 0100 to study its effect on the sleep EEG and on concomitant hormonal secretion of cortisol and growth hormone. In comparison to placebo, the peptide produced signs of general activation associated with specific deteriorating effects on the quality of sleep. Sleep onset latency and intermittent wakefulness were increased, slow wave sleep was reduced, but only during the first 3 hours of the sleep period. The nocturnal secretory patterns of cortisol and growth hormone were unaffected by HOE 427. These effects are different from those reported in similar studies in which corticotropin-releasing hormone (CRH) was applied in humans, and they suggest that peripherally administered neuropeptides have specific nonendocrine behavioral effects.     

Characterization of a Marine Bacterium Associated with Crassostrea virginica (the Eastern Oyster)

A gram-negative bacterium found to be closely associated with oysters has been isolated and characterized. The organism, designated LST, has a generation time of 106 min in Marine broth under optimal growth conditions at 25°C. During the decline phase of growth, it exhibits a morphological transition from a motile rod (ca. 1 μm in length) to an elongated, 3- to 40-μm, nonmotile, tightly coiled helix. LST synthesizes and releases a pigment in the stationary and decline phases of growth. Identified as melanin on the basis of chemical properties and UV absorbance maxima, the pigment comprises polymers of heterogeneous molecular weights, ranging from 12,000 to 120,000. The guanosine-plus-cytosine content of the LST DNA is 46%, and results of phenetic analysis and DNA-DNA hybridization indicate that this bacterium represents a new species. LST adheres to a variety of surfaces, including glass, plastics, and oyster shell, and has been shown to promote the settlement of oyster larvae.     

Histophotometric Evaluation of Glutamate Dehydrogenase Activity of the Rat Hippocampal Formation During Postnatal Development,with Special Reference to the Glutamate Transmitter Metabolism

Transmitter glutamate/aspartate synthesis is known to proceed along different metabolic pathways. In this light, the functional relevance of glutamate dehydrogenase in postnatally maturing glutamatergic/aspartatergic structures was studied by means of quantitative enzyme histochemistry. The basic requirements concerning the kinetics and calibration of the histochemical glutamate dehydrogenase reaction used were proved to be met in order to obtain valid quantitative data. The histochemically demonstrable activity of glutamate dehydrogenase (EC 1.4.1.3) in the hippocampal formation of the rat increased markedly during postnatal development. On day 30, the distribution pattern observed was similar to that in adult animals. While the enzyme activity rose within cell body layers from day 0 to day 30 by 240-285%, the increase in neuropil layers was found to be up to 830%. Maximum values were seen in the stratum lacunosum-moleculare of CA1 and CA3 and the stratum moleculare of the dentate fascia on day 30. Since the hippocampal neuropil is supposed to be copiously provided with glutamatergic (and aspartatergic?) structures which become functional in rats during the first weeks of postnatal life, the increase in enzyme activity is discussed to be primarily a consequence of maturing synaptic systems using glutamate and/or aspartate as transmitters.     

Requirements for antiribosomal activity of pokeweed antiviral protein

It has been known for some time that pokeweed antiviral protein acts by enzymatically inhibiting protein synthesis on eucaryotic ribosome systems. The site of this action is known to be the ribosome itself. In this paper we show that the pokeweed antiviral protein reaction against ribosomes is a strong function of salt concentrations, where 160 mM K⁺ and 3 mM Mg²⁺ retards the reaction, while 20 mM K⁺ and 2 mM Mg²⁺ allows maximum reaction rate. It is also shown, however, that an unidentified protein in the postribosomal supernatant solution, together with ATP, allows the ribosome to be attacked even in the presence of high salt. Kinetic analysis of the antiviral protein reaction has been carried out under both sets of conditions, and reveals that the turnover number for the enzyme is about 300–400 mol/mol per min. in each case. The K_m for ribosomes is 1 μM in the presence of low salt and 0.2 μM at higher salt in the presence of postribosomal supernatant factors plus ATP. The antiviral protein reaction is also shown to be pH dependent and is controlled by a residue with pK_a value of approx. 7.0, apparently a histidine. Stoichiometric reaction of the enzyme with iodoacetamide results in a significant loss of antiribosomal activity.     

Design and preclinical testing of an anti-CD41 CAR T cell for the treatment of acute megakaryoblastic leukaemia

Acute megakaryoblastic leukaemia (AMkL) is a rare subtype of acute myeloid leukaemia (AML) representing 5% of all reported cases, and frequently diagnosed in children with Down syndrome. Patients diagnosed with AMkL have low overall survival and have poor outcome to treatment, thus novel therapies such as CAR T cell therapy could represent an alternative in treating AMkL. We investigated the effect of a new CAR T cell which targets CD41, a specific surface antigen for M7-AMkL, against an in vitro model for AMkL, DAMI Luc2 cell line. The performed flow cytometry evaluation highlighted a percentage of 93.8% CAR T cells eGFP-positive and a limited acute effect on lowering the target cell population. However, the interaction between effector and target (E:T) cells, at a low ratio, lowered the cell membrane integrity, and reduced the M7-AMkL cell population after 24 h of co-culture, while the cytotoxic effect was not significant in groups with higher E:T ratio. Our findings suggest that the anti-CD41 CAR T cells are efficient for a limited time spawn and the cytotoxic effect is visible in all experimental groups with low E:T ratio.     

Liming induced stimulation of the amino acid metabolism in mycorrhizal roots of Norway spruce (Picea abies [L.] Karst.)

Localization and activity of three enzymes involved in the amino acid metabolism of ectomycorrhizas were investigated within an interdisciplinary experiment performed in a mature Norway spruce stand in Southern Germany (Höglwald). The enzymes NAD-glutamate dehydrogenase and aspartate aminotransferase were present in root cells, whereas aminopeptidase was found in mycorrhizas of Norway spruce such as Piceirhiza nigra and those with the fungi Cenococcum geophilum, Elaphomyces sp., Russula ochroleuca and Tylospora sp. Mycorrhizas growing in the humus layer contained about double the amount of protein found in those taken from the upper mineral soil (0–5 cm).Acid irrigation of the soil had no effect on the activity of any of the investigated enzymes, soluble protein or total N-contents irrespective of whether roots were taken from the organic layer or from the upper mineral soil. Liming, however, stimulated the activity of the three enzymes in mycorrhizas of the organic layer (O_f+O_h) whereas it had no effect on the activity of the investigated enzymes of mycorrhizas in the upper mineral soil. This effect is attributed to increased contents of soluble organic nitrogen compounds in the soil of the limed plots as compared to the unlimed plots.     

Effect of visual deprivation on neurotransmitter receptor development in the rat visual system

The effect of monocular deprivation (covering one eye on the 11th posnatal day) and rearing in darkness (the animals were born, developed, and killed with total exclusion of light) on development of -adrenergic, serotoninergic, muscarinic cholinergic, glutamatergic, and benzodiazepine receptors in primary visual structures (visual cortex, lateral geniculate body, superior colliculus, and retina) was investigated in rats. For quantitative analysis of neurotransmitter receptors, the technique of ligand binding was used. It was shown that monocular deprivation affects the development of -adrenergic, serotoninergic, and glutaminergic receptors mainly in the lateral geniculate body and retina, whereas rearing in darkness affects mainly the development of serotoninergic receptors in the superior colliculus. The development of receptors of the cholinergic neurotransmitter system is disturbed only temporarily by visual deprivation. Changes found in receptor development after visual deprivation indicate altered activity of different neurotransmitter systems in corresponding visual structures.P. Flechsig Brain Research Institute, Leipzig, East Germany. Karl Marx University, Leipzig, East Germany. Translated from Neirofiziologiya, Vol. 16, No. 5, pp. 691–701, September–October, 1984.