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Biomedical subjects

M Young

Publications and source records attributed to M Young.

At least 397 records · Page 22Linked to original sources
PubMed1978

Antagonism of central histamine H1 receptors by antipsychotic drugs.

The activity of 8 widely antipsychotic drugs as antagonists of central histamine H1 receptors was determined from the inhibition of the binding of 3H-mepyramine to a membrane fraction from guinea-pig brain. The phenothiazines examined, clorpromazine, fluphenazine, thioridazine and trifluoperazine, were all potent H1 antagonists. Both alpha- and beta-flupenthixol were potent inhibitors, but butaclamol, although less potent, showed stereospecificity. Haloperidol and spiperone were markedly weaker antihistamines than the phenothiazines.

Animals↗
PubMed1978

Secretagogue-mediated discharge of nerve growth factor from granular tubules of male mouse submandibular glands: an immunocytochemical study.

Submandibular glands of male mice were stained for nerve growth factor by light microscopic immunocytochemistry. Nerve growth factor (NGF) was present in the granules of granular tubule cells, with the immunoreactive material often concentrated at the periphery of granules. Administration of the alpha-adrenergic agent, phenylephrine, to animals resulted in a marked depletion of NGF-containing granules from granular tubules. Some release also occurred following administration of the beta-adrenergic agent, isoproterenol. Cholinergic stimulation (pilocarpine) did not result in appreciable loss of immunoreactive granules from these cells. In vitro results were not as clear cut, immunocytochemically, as those obtained with intact animals. It is concluded that discharge of NGF from male mouse submandibular glands is mediated predominantly by alpha-adrenergic activation, and that this phenomenon is readily demonstrated in the intact animal.

Animals↗
PubMed1978

Nerve growth factor: a protease that can activate plasminogen.

The single, highly stable form of mouse submandibular gland nerve growth factor (NGF), prepared as described by Young et al. [(1978) Biochemistry 17, 1490--1498] is a protease of restricted specificity that can convert plasminogen to plasmin. In the absence of plasminogen, NGF is not fibrinolytic, nor does it hydrolyze casein at a measurable rate. Treatment of NGF with diisopropyl fluorophosphate inhibits its ability to activate plasminogen as well as its capacity to hydrolyze certain synthetic arginine esters. These results indicate that NGF is a member of the class of serine proteases. Since NGF is known to be secreted at high concentrations in mouse saliva, it may serve to activate plasminogen (with subsequent fibrinolysis) somewhere in the alimentary tract. Plasminogen activation is the only known action of NGF upon a biologically important non-neural substrate.

Animals↗
PubMed1977

Dissociation of the 7S-nerve growth factor complex in solution.

Sedimentation and gel-filtration studies of mouse submandibular gland 7S-nerve growth factor (NGF) reveal that this complex dissociates to yield its components at concentrations much higher than those required to exhibit biological activity. Results further indicate that the alpha and gamma protein c omponents of the 7S-NGF complex probably play no role in its biological activity when tested in vitro. The dissociation behavior of 7S-NGF is quite different from the properties of very dilute solutions of the NGF secreted by mouse L cells and of that present in fresh, unpurified submandibular gland homogenates, since both of these proteins display high molecular weights at concentrations where 7s-NGF is fully dissociated. Thus, it could be that 7S-NGF is not the form in which NGF exists in the mouse submandibular gland.

Animals↗
PubMed1977

Determination of the absolute configuration at C-20 and C-24 of ergosterol in Ascomycetes and Basidiomycetes by proton magnetic resonance spectroscopy.

Samples of ergosterol isolated from Saccharomyces cerevisiae, Neurospora crassa, and Agaricus sp., and commercial ergosterol all displayed identical proton magnetic resonance (PMR) spectra at 220 MHz. From the effects produced on the doublet for C-21 by epimerization at C-20 and C-24 in sterols of known configuration, the absolute configurations at these positions in ergosterol were determined. The data demonstrate that ergosterol from both Ascomycetes and Basidiomycetes is the same and that at C-20 and C-24, the two H-atoms are on the alpha-side of the asymmetric carbon atoms and that C-22 is trans-oriented with respect to C-13 about the 17(20)-bond.

Ascomycota↗
PubMed1977

Synthesis and secretion of a high molecular weight form of nerve growth factor by skeletal muscle cells in culture.

Rat skeletal muscle cells and a cloned myogenic cell line synthesize and secrete in culture a molecule that is immunologically and biologically indistinguishable from the active form of nerve growth factor (NGF) from mouse submandibular gland. This protein can be detected in medium conditioned by muscle cells both before and after fusion and in the soluble fraction of muscle cell homogenates. Chromatographic data also reveal that the molecular properties of muscle cell NGF differ from those of the growth factor purified from mouse submandibular glands. Muscle cell NGF has a molecular weight between 140,000 and 160,000, whereas purified mouse gland NGF has a molecular weight of 26,000. The biologic function of muscle cell NGF is not known, although it could be that it plays some role relating to the association of nerves and muscle in vivo.

Animals↗
PubMed1977

Molecular properties of the nerve growth factor secreted by L cells.

The molecular size and stability of the nerve growth factor (NGF) secreted in culture by L cells have been studied by sedimentation and gel filtration chromatography. Results indicate that L cell NGF has a molecular weight of 160,000. It contains as part of its structure a protein component that is biologically, immunologically, and electrophoretically indistinguishable from the biologically active factor purified from mouse submandibular glands. However, unlike pure gland NGF, L cell NGF is highly stable in solution, and this finding indicates that L cell NGF is a form of the factor different from that previously described.

Animals↗
PubMed1977

Nerve growth factor in mouse serum and saliva: role of the submandibular gland.

The concept that the salivary gland of the mouse is an endocrine organ for nerve growth factor (NGF) has been reexamined. Serum concentrations of the protein have been measured by radioimmunoassay in male and female mice and in mice from which the submandibular glands were removed. In spite of the fact that the submandibular glands of male mice contained more NGF than did those of female mice, no sex differences in circulating concentrations of the factor were detected. Furthermore, serum concentrations of NGF did not change after submandibular gland removal or after administration of several autonomic agonists. These results indicate that the submandibular glands are not endocrine organs with respect to NGF. On the other hand, extremely high concentrations of the factor are normally secreted in mouse saliva at levels that reflect the sex differences in the amount of NGF present in the glands. This finding suggests that the salivary gland is an exocrine organ for NGF and that the protein may play a biological role in saliva.

Animals↗
PubMed1977

Molecular properties of the nerve growth factor secreted in mouse saliva.

Some molecular properties of the nerve growth factor (NGF) secreted in mouse saliva and that present in submandibular glands have been measured for comparison with previously studied forms of NGF. The results show that mouse saliva contains two biologically active NGF species. One has a molecular weight near 114,000, and the other, a molecular weight of 13,000. The larger form is being continuously degraded to yield the smaller one, probably as a result of a slow enzymatic process. Virtually identical results were obtained with crude submandibular gland extracts. The larger NGF is neither the well-known 7S NGF nor 2.5S NGF. Our results indicate that the larger salivary NGF is the naturally occurring form of NGF as it exists in the submandibular gland and as it is secreted in saliva. Its biological properties and its function in saliva, if any, remain to be elucidated.

Animals↗