Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:3.4.24.64 (MPP)
 1,876 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1-(o-methoxyphenyl)-piperazine (o-MPP) is regarded as an antagonist of the dopamine receptor. Its effects were studied for the hind limb flexor reflex in the spinal rat, the body temperature in rats maintained at ambient temperature of 28 degrees C and stereotypy induced in rats by a low dose of apomorphine (0.5 mg/kg). o-MPP (2-12.5 mg/kg) stimulated the flexor reflex and, in higher doses (10-40 mg/kg), elevated the body temperature of heat-adapted rats. Both effects were inhibited by central serotonin receptor blocking agents--cyproheptadine or metergoline. Low doses of o-MPP (below 5 mg/kg) did not affect stereotypy induced by apomorphine; higher doses (5-25 mg/kg) attenuated the stereotypy in a dose-dependent manner. The results obtained suggest that o-MPP may facilitate the central serotonergic transmission similarly as several other phenylpiperazines. The role of this effect in the "antidopamine" action of o-MPP is discussed.
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PMID:A serotonergic component in the central action of 1-(o-methoxyphenyl)-piperazine. 666 37

This paper reports further psychophysical studies on a multiple-channel cochlear implant patient evaluating the feasibility of a speech processing strategy which converts the acoustic fundamental frequency to electric repetition rate, the second-formant frequency to electrode position, and the acoustic amplitude to current level. The first four studies evaluated the use of a special pulse pattern to minimize the loudness variation with electric repetition rate. The chosen pulse pattern consisted of multiple pulses occurring in the first half of each repetitive period (MPP) in contrast to the more conventional pattern with a single pulse per period (SPP). The results showed that MPP approximately equalized the loudness variation with repetition rate. The dynamic range of current, the pitch variation with repetition rate, and the difference limens for repetition rate were found to be similar to MPP and SPP. Two other studies investigated interaction between electrode position and repetition rate (RR). The first of these showed that the patient could make use of information provided by rising or falling RR trajectories superimposed on individual electrodes or electrode trajectories as an indicator of the direction of intonation variation. The second of these studies showed that the dissimilarities amongst the hearing sensations produced by steady-state stimuli differing in electrode position and repetition rate were characterized by two perceptual components, relating to the two electric parameters, respectively.
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PMID:Psychophysical studies evaluating the feasibility of a speech processing strategy for a multiple-channel cochlear implant. 668 34

Today eyes with massive periretinal proliferation which are often seen after uncured retinal detachments or after perforating injuries can be cured at least in 25 to 35% of the cases, even with modern surgical techniques. This is due to proliferation of cells, which enter through different pathways--retinal tears, perforating wounds of sclera and chorioidea, damaged retina or retinal vessels--into the vitreous and form membranes, which prevent the retina to attach. In the vitreous gel these cells of different origin can transform into fibroblast-like or myofibroblast-like cells. They also behave in the same way like fibroblasts or myofibroblasts and cause a kind of excessive wound healing and scar formation in the vitreous cavity. With the use of modern vitreous techniques we could cure nearly 43% of 14 patients with MPP after uncured retinal detachments or after perforating injuries. Because mechanical removal of intravitreal and periretinal membranes alone turned out to be unsuccessful in nearly 60%, methods of medical therapy to suppress this cell-activity seemed to be rather needed. By animal experiment we tried to produce retinal detachments by transplantation of homologue fibroblasts into the vitreous cavity of rabbit eyes, and observed traction detachments in 55% of the eyes. Histologic examination showed a rapid change of loose, round fibroblasts into elongated cells with long nuclei, which formed strands and caused vasoproliferation, especially where the strand reached the rabbit retina. By means of autoradiography the peak of cell activity turned out to be in the 3rd week after cell-transplantation and further examinations of the optic disc showed, that the vascular endothelium cell might be one source of the proliferation. There was no difference between the number of eyes which developed retinal detachment in the aphakic eyes and in the lentectomized and vitrectomized eyes, but we observed the clinical appearance of MPP earlier and more pronounced in the lentectomized and vitrectomized eyes. In the last experiment we tried to inhibit intraocular proliferation with intravitreal dexamethasone alcohol. This leaded to a significant reduce of the number of experimental detachments and vasoproliferations.
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PMID:[Clinical and experimental results in the treatment of massive periretinal proliferation (MPP), a retinal detachment with a most unfavorable prognosis]. 676 5

Two classes of immunomodulators of bacterial origin, peptidoglycan derivatives and lipopolysaccharides, are able to block in vitro the production of plasminogen activator by elicited macrophages: the release of the enzyme into the medium is inhibited and the intracellular activity reduced. In the case of peptidoglycan derivatives, high molecular weight compounds like WSA (water-soluble adjuvant) are stronger inhibitors than small molecules like MPP (muramyl pentapeptide). MDP (muramyl dipeptide) gives partial inhibition only. WSA (at 100 micrograms/ml) completely inhibits plasminogen activator production; the inhibition is reversible and specific. LPS is active at low concentrations (25-100 ng/ml). At concentrations higher than 50-100 ng/ml the action of LPS becomes irreversible and less specific. Peptidoglycan-derived immunomodulators can inhibit plasminogen activator production in the presence of polymixin B or in the case of macrophages obtained from C3H/HeJ mice; LPS is inactive under such conditions.
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PMID:Regulation of plasminogen activator secretion in mouse peritoneal macrophages. II. Inhibition by immunomodulators of bacterial origin. 680 2

The metabolic fate in mice of two 14C labelled meso-A2pm containing muramyl-peptides, the muramyl-tripeptide (Ac-Mur-L-Ala-gamma-D-Glu-14C-meso-A2pm) (MTP) and the muramyl-pentapeptide (Ac-Mur-L-Ala-gamma-D-Glu-meso-A2pm-14C-D-Ala-14C-D-Ala) (MPP) has been studied. As with 14C-MDP, the radioactive muramyl-tripeptide and muramyl-pentapeptide disappear rapidly from the organs and the radioactivity is found mainly in the urine. In contrast to MDP, the two meso-A2pm containing muramyl-peptides are not excreted intact in the urine. In both cases labelled fragments have been identifed: meso-A2pm from MTP and the tetrapeptide gamma-D-Glu-meso-A2pm-D-Ala-D-Ala from MPP. The ability of the two muramyl-peptides to increase nonspecific resistance of mice to Klebsiella infection was also investigated. The muramyl-pentapeptide injected i.v. one day before a lethal dose of K. pneumoniae protects both adult and neonate mice, as does MDP itself; the muramyl-tripeptide is inactive.
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PMID:Fate of two 14C labelled muramyl peptides: Ac-Mur-L-Ala-gamma-D-Glu-meso-A2pm and Ac-Mur-L-Ala-gamma-D-Glu-meso-A2pm-D-Ala-D-Ala in mice. Evaluation of their ability to increase non specific resistance to Klebsiella infection. 704 71

The authors used the unsecured balloon buckle of Lincoff and Kreissig in 15 cases during a six-month period (September 1981 to March 1982) at the Ist Eye Clinic in Vienna and the Eye Department in Salzburg. Cases were selected in which one large tear and a circumscribed detachment existed, as well as detachments with only one tear or a group of holes which did not exceed one hour in extent. After an observation period of between three and nine months the detachment was cured with the balloon buckle in 12 eyes, while in three eyes it failed; in two of them a cure was achieved by permanent buckle operation. In one eye the find result was MPP. This method seems particularly suited to cases where cryocoagulation or photocoagulation alone is too dangerous, but on the other hand a permanent buckle operation might cause muscle disturbances and irritating diplopia in eyes with usually good visual acuity before and after surgery. Further experience with the unsecured balloon buckle will show how far the indications for this method can be extended.
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PMID:[Preliminary results with the Lincoff-Kreissig balloon buckle]. 716 71

We have developed a new plate-type membrane oxygenator (MO) using a microporous polysulfone membrane. The MO is compact, handy and very easy to set up, and has easy defoaming. The MO is primed with crystalloid; through the cardiotomy reservoir, air exits across the porous membrane and is removed through ports in the membrane oxygenator. Performance and clinical use have shown that the PS oxygenator has a better gas exchange than conventional silicone oxygenators, with appropriate O2/CO2 balance and a capability for controlling oxygen and carbon dioxide separate exchange. The advantage of the MPS membrane is improved blood compatibility, and TABLE 1. BLOOD GAS ANALYSIS DURING PERFUSION Mean +/- SD Range Blood Flow (L/min) 1.56 +/- 0.29 1.04-2.12 Gas Flow (L/min) 1.89 +/- 0.73 0.5-3.0 Gas/Blood Flow Ratio 1.19 +/- 0.38 0.45-1.95 pH venous 7.340 +/- 0.083 7.220-7.443 arterial 7.390 +/- 0.080 7.272-7.507 pCO2 (mm Hg) venous 44.8 +/- 10.8 29.6-65.2 arterial 35.7 +/- 7.1 23.8-51.1 pO2 (mm Hg) venous 46.4 +/- 17.2 26.1-98.8 arterial 276.3 +/- 135.6 66.1-533.4 SO2 (%) venous 71.9 +/- 14.7 35.7-95.6 arterial 98.7 +/- 2.3 91.5-99.9 a larger number of small pores than the MPP membrane. Vapor loss, thought to be typical of microporous membranes, was found to be negligibly small. Use of the PS oxygenator for open heart surgery on 15 pediatric patients proved satisfactory, and in the future the oxygenator may prove useful for prolonged perfusions.
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PMID:Development and clinical application of a new membrane oxygenator using a microporous polysulfone membrane. 716 60

After a brief survey on the indications of the Lincoff buckling technique, the limits of this method are demonstrated by means of varions cases. Then the application of the intraocular gas tamponade with sulfur hexafluoride (SF6) as an additional measure is recommended and described. The combination with vitrectomies in cases of advanced vitreous complications (MPP, proliferations, haemorrhages) is indicated.
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PMID:[Limits of episcleral buckling procedure (author's transl)]. 720 85

The FLAG peptide has been widely used as a multi-purpose tag for the identification and detection of recombinant FLAG fusion proteins. The practicability of this approach depends on specific detection of FLAG fusion proteins with no or very little cross-reactivity to cellular proteins. We have isolated a rat cDNA clone coding for a new splicing isoform of Mg2+ dependent protein phosphatase beta (MPP beta) by screening a rat brain expression library with monoclonal antibody Anti-FLAG M2. MPP beta reacts strongly both as a MPP beta-beta-galactosidase- and as a glutathione S-transferase fusion protein with anti-FLAG M2 antibodies. Sequence analysis of MPP beta revealed a sequence motif with five out of eight amino acid residues identical to the FLAG peptide hitherto believed to be mono-specific.
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PMID:Monoclonal anti-FLAG antibodies react with a new isoform of rat Mg2+ dependent protein phosphatase beta. 753 4

N-Methyl, 4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) produces experimental parkinsonism after oxidation to N-methylpyridinium ion (MPP+), accumulation in dopamine neurons and concentration in mitochondria. Inhibition by MPP+ of mitochondrial electron transport impairs respiratory function, but the molecular mechanisms of cell death are not clear. We tested the hypothesis that locally produced nitric oxide is a key component in MPTP toxicity by providing a necessary intermediate in the production of hydroxyl free radicals. Inhibition of nitric oxide synthase reduced MPP(+)-induced hydroxyl radical formation in striatum and MPTP toxicity to nigrostriatal dopamine terminals, but did not interfere with inhibition of complex-I activity. Nitric oxide appears to be necessary for hydroxyl free radical generation in MPP+ toxicity and may play a role in neuronal degeneration in Parkinson's disease.
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PMID:Reduction of MPP(+)-induced hydroxyl radical formation and nigrostriatal MPTP toxicity by inhibiting nitric oxide synthase. 753 21


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