A MAPPING OF OXIDATIVE ENZYMES IN THE HUMAN BRAIN *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65177/1/j.1471-4159.1962.tb11860.x.pd

A QUANTITATIVE MAPPING OF ALKALINE PHOSPHATASE IN THE BRAIN OF THE RHESUS MONKEY *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65477/1/j.1471-4159.1966.tb07513.x.pd

PROXIMO-DISTAL INCREASE OF ENZYMIC ACTIVITY IN THE DORSAL SPINAL TRACTS *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65919/1/j.1471-4159.1964.tb06151.x.pd

An enzyme histochemical study of torpedoes and dendritic swellings in the cerebellum

In 8 cases, the following enzymes were studied in the dendritic swellings and torpedoes of Purkinje cells of cerebellum: succinic dehydrogenase, cytochrome oxidase, lactic dehydrogenase, NAD-diaphorase, alkaline phosphatase, acid phosphatase, acetyl cholinesterase and nonspecific cholinesterase. Activity of the oxidative enzymes was always extremely high in the dendritic swellings, but varied greatly among cases in the torpedoes; 4 cases showed very weak activity of oxidative enzymes in torpedoes, while 4 other cases showed an intense reaction. Dendritic swellings and torpedoes exhibited no alkaline phosphatase, acetyl cholinesterase, or nonspecific cholinesterase activity. In Dendritenanschwellungen und Torpedos der Purkinje-Zellen des Kleinhirns von 8 Fällen wurden die folgenden Enzyme untersucht: Bernsteinsäure-Dehydrogenase, Cytochrom-Oxidase, Milchsäure-Dehydrogenase, NAD-Diaphorase, alkalische Phosphatase, saure Phosphatase, Acetylcholinesterase und unspezifische Cholinesterase. Die Aktivität der oxidativen Enzyme war in den Dendritenanschwellungen immer sehr hoch, in den Torpedos aber von Fall zu Fall sehr unterschiedlich: 4 Fälle zeigten nur sehr geringe Aktivität, die 4 anderen jedoch eine sehr intensive Reaktion. Die Dendritenanschwellungen und Torpedos zeigten keine Aktivität der alkalischen Phosphatase, Acetylcholinesterase oder unspezifischen Cholinesterase.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/47226/1/401_2004_Article_BF00687526.pd

A COMPARATIVE MAPPING OF ENZYMES INVOLVED IN HEXOSEMONOPHOSPHATE SHUNT AND CITRIC ACID CYCLE IN THE BRAIN *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/66082/1/j.1471-4159.1963.tb05042.x.pd

A COMPARISON OF CHOLINESTERASE DISTRIBUTION IN THE CEREBELLUM OF SEVERAL SPECIES *

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/65142/1/j.1471-4159.1964.tb06717.x.pd

Inorganic impact modifier and processing aid for PVC

An amorphous silica, SIDISTAR has been investigated as an impact modifier for rigid PVC. Optimal dispersion of the silica as primary particles is essential and this can be achieved by incorporating it at an early stage of the mixing process before other fillers are added. This ensures that the PVC grains are coated with SIDISTAR. This material is able to function as an impact modifier via the cavitation mechanism and it will also improve the dispersion of the other ingredients in the compound. It was found that SIDISTAR delayed gelation of the PVC compound, but this could be avoided by minor changes in formulation and processing conditions. Reduction in gelation time resulted in improved impact performance. Furthermore, compounds containing SIDISTAR possessed a wide processing window

PTP-1B is an essential positive regulator of platelet integrin signaling

Outside-in integrin αIIbβ3 signaling is required for normal platelet thrombus formation and is triggered by c-Src activation through an unknown mechanism. In this study, we demonstrate an essential role for protein–tyrosine phosphatase (PTP)–1B in this process. In resting platelets, c-Src forms a complex with αIIbβ3 and Csk, which phosphorylates c-Src tyrosine 529 to maintain c-Src autoinhibition. Fibrinogen binding to αIIbβ3 triggers PTP-1B recruitment to the αIIbβ3–c-Src–Csk complex in a manner that is dependent on c-Src and specific tyrosine (tyrosine 152 and 153) and proline (proline 309 and 310) residues in PTP-1B. Studies of PTP-1B–deficient mouse platelets indicate that PTP-1B is required for fibrinogen-dependent Csk dissociation from αIIbβ3, dephosphorylation of c-Src tyrosine 529, and c-Src activation. Furthermore, PTP-1B–deficient platelets are defective in outside-in αIIbβ3 signaling in vitro as manifested by poor spreading on fibrinogen and decreased clot retraction, and they exhibit ineffective Ca2+ signaling and thrombus formation in vivo. Thus, PTP-1B is an essential positive regulator of the initiation of outside-in αIIbβ3 signaling in platelets

Glycoprotein Ib activation by thrombin stimulates the energy metabolism in human platelets

<div><p>Thrombin-induced platelet activation requires substantial amounts of ATP. However, the specific contribution of each ATP-generating pathway <i>i</i>.<i>e</i>., oxidative phosphorylation (OxPhos) versus glycolysis and the biochemical mechanisms involved in the thrombin-induced activation of energy metabolism remain unclear. Here we report an integral analysis on the role of both energy pathways in human platelets activated by several agonists, and the signal transducing mechanisms associated with such activation. We found that thrombin, Trap-6, arachidonic acid, collagen, A23187, epinephrine and ADP significantly increased glycolytic flux (3–38 times <i>vs</i>. non-activated platelets) whereas ristocetin was ineffective. OxPhos (33 times) and mitochondrial transmembrane potential (88%) were increased only by thrombin. OxPhos was the main source of ATP in thrombin-activated platelets, whereas in platelets activated by any of the other agonists, glycolysis was the principal ATP supplier. In order to establish the biochemical mechanisms involved in the thrombin-induced OxPhos activation in platelets, several signaling pathways associated with mitochondrial activation were analyzed. Wortmannin and LY294002 (PI3K/Akt pathway inhibitors), ristocetin and heparin (GPIb inhibitors) as well as resveratrol, ATP (calcium-release inhibitors) and PP1 (Tyr-phosphorylation inhibitor) prevented the thrombin-induced platelet activation. These results suggest that thrombin activates OxPhos and glycolysis through GPIb-dependent signaling involving PI3K and Akt activation, calcium mobilization and protein phosphorylation.</p></div