Pipecolic Acids
2-Aminoadipic Acid
Saccharopine Dehydrogenases
Rhodotorula
Mitosporic Fungi
Picolinic Acids
Oxidoreductases Acting on CH-NH Group Donors
Effects of (+)-HA-966, CGS-19755, phencyclidine, and dizocilpine on repeated acquisition of response chains in pigeons: systemic manipulation of central glycine sites. (1/209)
The effects of i.m. injections of (+)-HA-966, a glycine-site antagonist at the N-methyl-D-aspartate (NMDA) subtype of the glutamate receptor, its enantiomer (-)-HA-966, the competitive glutamate antagonist CGS-19755, the uncompetitive glutamate antagonists phencyclidine and dizocilpine, and the micro opioid agonist morphine were evaluated in a repeated acquisition task in pigeons. All of the drugs produced dose-dependent decreases in rates of responding. The NMDA receptor and channel blockers and (+)-HA-966 appeared to have a greater effect on acquisition than did morphine at doses that did not fully suppress responding. The rate suppression and learning impairment produced by a large dose of (+)-HA-966 (100 mg/kg) were completely prevented by coadministration of the glycine-site agonist D-serine (560 mg/kg) but not by its enantiomer, L-serine (1000 mg/kg). D-Serine, however, produced incomplete antagonism of the effects of dizocilpine and phencyclidine and failed to alter those of CGS-19755. These findings provide evidence that reducing the activity of the NMDA subtype of the glutamate receptor through pharmacological action at any of three sites produces similar decrements in acquisition, and those produced through antagonism of the glycine site are differentially sensitive to the glycine-site agonist D-serine. (+info)Effect of thrombin inhibition in vascular dementia and silent cerebrovascular disease. An MR spectroscopy study. (2/209)
BACKGROUND AND PURPOSE: Silent cerebrovascular disease (CVD) has been proposed as a predisposing condition for clinically overt stroke and vascular dementia. Recently, we found increased thrombin generation in silent CVD patients. Here, we report the effect of thrombin inhibition using a potent selective thrombin inhibitor on the cerebral metabolism and function in peripheral arterial occlusive disease (PAOD) patients with or without silent CVD. METHODS: We examined 17 mild chronic PAOD patients, including 2 cases of vascular dementia. We divided the patients into 2 groups: 1 was the advanced CVD group with multiple lacunar infarction and/or advanced periventricular hyperintensity detected by brain MRI (n=12), and the other was the no CVD group that had none of these abnormalities (n=5). We assessed the cerebral biochemical compounds in the deep white matter area and cerebellar hemisphere (8 cm3) by proton MR spectroscopy before and after infusion of argatroban (10 mg/d IV) over 2 hours for 7 days. RESULTS: The ratio of N-acetylasparate (NAA) to total creatine (Cre) in the deep white matter area was significantly lower in the advanced CVD group than in the no CVD group, whereas there were no significant differences in this ratio in the cerebellar hemisphere between the 2 groups. In the former group, this decreased NAA/Cre ratio significantly increased after argatroban therapy, whereas there was no change in the latter group. The 2 patients with vascular dementia showed clinical improvement with marked increases in the NAA/Cre ratio and mini-mental score. CONCLUSIONS: These results suggest that increased thrombin generation may have some pathophysiological roles in developing vascular dementia and its chronic predisposing conditions. Thrombin inhibition may break this vicious cycle and lead to clinical improvement. (+info)Complex behavioral strategy and reversal learning in the water maze without NMDA receptor-dependent long-term potentiation. (3/209)
Successful performance of the water maze task requires that rats learn complex behavioral strategies for swimming in a pool of water, searching for and interacting with a hidden platform before its spatial location can be learned. To evaluate whether NMDA receptor-dependent long-term potentiation (NMDA-LTP) is required for learning the required behavioral strategies, rats with NMDA-LTP blocked by systemic pharmacological treatment were trained in the behavioral strategies using simplified and stepwise training methods. Despite the blockade of NMDA-LTP in the dentate gyrus and hippocampal area CA1, rats learned the required behavioral strategies and used them to learn both initial and reversed platform locations. This is the first evaluation of the role of NMDA-LTP specifically in behavioral strategy learning. Although hippocampal NMDA-LTP might contribute to the water maze task, this form of LTP is not essential for learning complex behavioral strategies or multiple hidden platform locations. (+info)SPD 502: a water-soluble and in vivo long-lasting AMPA antagonist with neuroprotective activity. (4/209)
Accumulating preclinical data suggest that compounds that block the excitatory effect of glutamate on excitatory amino acid receptors may have neuroprotective effects and utility for the treatment of neurodegeneration after brain ischemia. In the present study, the in vitro and in vivo pharmacological properties of the novel glutamate antagonist SPD 502 [8-methyl-5(4-(N,N-dimethylsulfamoyl)phenyl)-6,7, 8,9,-tetrahydro-1H-pyrrolo[3,2-h]-isoquinoline-2, 3-dione-3-O-(4-hydroxybutyric acid-2-yl)oxime] are described. In binding studies, SPD 502 was shown to display selectivity for the [3H]alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid (AMPA)-binding site (IC50 = 0.043 microM) compared with the [3H]kainate- (IC50 = 81 microM), [3H]cis-4-phosphonomethyl-2-piperidine carboxylic acid-(CGS 19755), and [3H]glycine-binding sites (IC50 > 30 microM) in rat cortical membranes. In an in vitro functional assay, SPD 502 blocked the AMPA-induced release of [3H]gamma-aminobutyric acid from cultured mouse cortical neurons in a competitive manner with an IC50 value of 0.23 microM. Furthermore, SPD 502 potently and selectively inhibited AMPA-induced currents in cortical neurons with an IC50 value of 0.15 microM. In in vivo electrophysiology, SPD 502 blocked AMPA-evoked spike activity in rat hippocampus after i.v. administration with an ED50 value of 6.1 mg/kg and with a duration of action of more than 1 h. Furthermore, SPD 502 increased the seizure threshold for electroshock-induced tonic seizures in mice at i.v doses of 40 mg/kg and higher. In the two-vessel occlusion model of transient forebrain ischemia in gerbils, SPD 502 (10 mg/kg bolus injection followed by a 10 mg/kg/h infusion for 2 h) resulted in a highly significant protection against the ischemia-induced damage in the hippocampal CA1 pyramidal neurons. (+info)A multicenter, randomized study of argatroban versus heparin as adjunct to tissue plasminogen activator (TPA) in acute myocardial infarction: myocardial infarction with novastan and TPA (MINT) study. (5/209)
OBJECTIVES: This study examined the effect of a small-molecule, direct thrombin inhibitor, argatroban, on reperfusion induced by tissue plasminogen activator (TPA) in patients with acute myocardial infarction (AMI). BACKGROUND: Thrombin plays a crucial role in thrombosis and thrombolysis. In vitro and in vivo studies have shown that argatroban has advantages over heparin for the inhibition of clot-bound thrombin and for the enhancement of thrombolysis with TPA. METHODS: One hundred and twenty-five patients with AMI within 6 h were randomized to heparin, low-dose argatroban or high-dose argatroban in addition to TPA. The primary end point was the rate of thrombolysis in myocardial infarction (TIMI) grade 3 flow at 90 min. RESULTS: TIMI grade 3 flow was achieved in 42.1% of heparin, 56.8% of low-dose argatroban (p = 0.20 vs. heparin) and 58.7% of high-dose argatroban patients (p = 0.13 vs. heparin). In patients presenting after 3 h, TIMI grade 3 flow was significantly more frequent in high-dose argatroban versus heparin patients: 57.1% versus 20.0% (p = 0.03 vs. heparin). Major bleeding was observed in 10.0% of heparin, and in 2.6% and 4.3% of low-dose and high-dose argatroban patients, respectively. The composite of death, recurrent myocardial infarction, cardiogenic shock or congestive heart failure, revascularization and recurrent ischemia at 30 days occurred in 37.5% of heparin, 32.0% of low-dose argatroban and 25.5% of high-dose argatroban patients (p = 0.23). CONCLUSIONS: Argatroban, as compared with heparin, appears to enhance reperfusion with TPA in patients with AMI, particularly in those patients with delayed presentation. The incidences of major bleeding and adverse clinical outcome were lower in the patients receiving argatroban. (+info)L-proline and L-pipecolate induce enkephalin-sensitive currents in human embryonic kidney 293 cells transfected with the high-affinity mammalian brain L-proline transporter. (6/209)
The high-affinity mammalian brain L-proline transporter (PROT) belongs to the GAT1 gene family, which includes Na- and Cl-dependent plasma membrane carriers for neurotransmitters, osmolites, and metabolites. These transporters couple substrate flux to transmembrane electrochemical gradients, particularly the Na gradient. In the nervous system, transporters clear synapses and help to replenish transmitters in nerve terminals. The localization of PROT to specific excitatory terminals in rat forebrain suggests a role for this carrier in excitatory transmission (). We investigated the voltage regulation and electrogenicity of this novel transporter, using human embryonic kidney (HEK) 293 cells stably transfected with rat PROT cDNA. In physiological solutions between -140 and -40 mV, L-proline (PRO) and its six-member ring congener L-pipecolate (PIP) induced inward current. The current-voltage relationship and the variance of current fluctuations were similar for PRO- and PIP-induced current, and the ratio of induced variance to the mean current ranged from 20 to 60 fA. Des-Tyr-Leu-enkephalin (GGFL), a competitive peptide inhibitor of PROT, reduced the rat PROT-associated current to control levels. GGFL alone did not elicit currents, and the GGFL-sensitive substrate-induced current was absent in nontransfected cells. Finally, GGFL inhibited PROT-mediated transport only when applied to the extracellular face of PROT. These data suggest that (1) PROT uptake is electrogenic, (2) individual transporter currents are voltage-independent, and (3) GGFL is a nonsubstrate inhibitor that interacts either with an extracellular domain of PROT or in an externally accessible pore. (+info)Glutamate release through volume-activated channels during spreading depression. (7/209)
Volume-sensitive organic anion channels (VSOACs) in astrocytes are activated by cell swelling and are permeable to organic anions, such as glutamate and taurine. We have examined the release of glutamate through VSOACs during the propagation of spreading depression (SD). SD was induced by bath application of ouabain in hippocampal brain slices and was monitored by imaging intrinsic optical signals, a technique that provides a measure of cellular swelling. The onset of SD was associated with increased light transmittance, confirming previous studies that cellular swelling occurs during SD. NMDA receptor antagonists, either noncompetitive (MK-801, 10-50 microM) or competitive (CGS-17355, 100 microM), reduced the rate of propagation of SD, indicating that glutamate release contributes to SD onset. SD still occurred in zero Ca(2+)-EGTA (0-Ca(2+)-EGTA) solution, a manipulation that depresses synaptic transmission. HPLC measurements indicated that, even in this solution, there was significant glutamate release. Two lines of experiments indicated that glutamate was released through VSOACs during SD. First, 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB), a blocker of VSOACs, depressed the rate of propagation of SD in a manner similar to NMDA antagonists. Second, NPPB inhibited the release of glutamate during SD in 0-Ca(2+)-EGTA external solution. These results indicate that cellular swelling during SD causes the activation of VSOACs and the release of glutamate by permeation through this channel. Cellular swelling is a result of neuronal activity and is observed during excitotoxicity. Therefore, glutamate release from VSOAC activation could occur under conditions of cell swelling and contribute to excitotoxic damage. (+info)L-Pipecolic acid oxidase, a human enzyme essential for the degradation of L-pipecolic acid, is most similar to the monomeric sarcosine oxidases. (8/209)
L-Pipecolic acid oxidase activity is deficient in patients with peroxisome biogenesis disorders (PBDs). Because its role, if any, in these disorders is unknown, we cloned the associated human gene and expressed its protein product. The cDNA was cloned with the use of a reverse genetics approach based on the amino acid sequence obtained from purified L-pipecolic acid oxidase from monkey. The complete cDNA, obtained by conventional library screening and 5' rapid amplification of cDNA ends, encompassed an open reading frame of 1170 bases, translating to a 390-residue protein. The translated protein terminated with the sequence AHL, a peroxisomal targeting signal 1. Indirect immunofluorescence studies showed that the protein product was expressed in human fibroblasts in a punctate pattern that co-localized with the peroxisomal enzyme catalase. A BLAST search with the amino acid sequence showed 31% identity and 53% similarity with Bacillus sp. NS-129 monomeric sarcosine oxidase, as well as similarity to all sarcosine oxidases and dehydrogenases. No similarity was found to the peroxisomal D-amino acid oxidases. The recombinant enzyme oxidized both L-pipecolic acid and sarcosine. However, PBD patients who lack the enzyme activity accumulate only L-pipecolic acid, suggesting that in humans in vivo, this enzyme is involved mainly in the degradation of L-pipecolic acid. (+info)Pipicolic acid is not a term that refers to a specific medical condition or disease. Instead, it is a metabolite that is involved in the body's metabolic processes.
Pipicolic acid is a type of organic compound called a cyclic amino acid, which is derived from the amino acid lysine. It is produced in the liver and is excreted in urine. Pipicolic acid has been found to have various functions in the body, including regulating the metabolism of lipids and bile acids.
Abnormal levels of pipicolic acid in the body may be associated with certain medical conditions, such as liver disease or genetic disorders that affect amino acid metabolism. However, pipicolic acid is not typically used as a diagnostic marker for these conditions.
In summary, pipicolic acid is a cyclic amino acid produced in the liver and involved in various metabolic processes in the body. Abnormal levels of pipicolic acid may be associated with certain medical conditions but are not typically used as diagnostic markers.
2-Aminoadipic acid (2-AAA) is a type of amino acid that is formed as a byproduct of the metabolism of lysine, which is an essential amino acid. It is not commonly considered a building block of proteins, but it does play a role in various biochemical pathways in the body.
Abnormally high levels of 2-AAA have been found in certain medical conditions, such as genetic disorders of lysine metabolism and in some neurodegenerative diseases like multiple sclerosis and Alzheimer's disease. However, it is not currently clear whether elevated levels of 2-AAA are a cause or a consequence of these conditions.
Research is ongoing to better understand the role of 2-AAA in human health and disease.
Saccharopine dehydrogenases are enzymes involved in the metabolism of the amino acid lysine. These enzymes catalyze the conversion of saccharopine, an intermediate compound in the lysine degradation pathway, into α-aminoadipic semialdehyde and glutamate. Saccharopine dehydrogenases play a crucial role in maintaining the balance of amino acids in the body and are found in various organisms, including bacteria, plants, and animals. In humans, mutations in the gene encoding one form of saccharopine dehydrogenase (Lysine Ketoglutarate Reductase/Saccharopine Dehydrogenase) have been associated with a rare genetic disorder called saccharopinuria, which is characterized by elevated levels of saccharopine in the urine and neurological symptoms.
Rhodotorula is a genus of unicellular, budding yeasts that are commonly found in the environment, particularly in damp and nutrient-rich places such as soil, water, and vegetation. They are characterized by their ability to produce carotenoid pigments, which give them a distinctive pinkish-red color.
While Rhodotorula species are not typically associated with human disease, they can occasionally cause infections in people with weakened immune systems or underlying medical conditions. These infections can occur in various parts of the body, including the respiratory tract, urinary tract, and skin.
Rhodotorula infections are usually treated with antifungal medications, such as fluconazole or amphotericin B. Preventing exposure to sources of Rhodotorula, such as contaminated medical equipment or water supplies, can also help reduce the risk of infection.
Mitosporic fungi, also known as asexual fungi or anamorphic fungi, are a group of fungi that produce mitospores (also called conidia) during their asexual reproduction. Mitospores are produced from the tip of specialized hyphae called conidiophores and are used for dispersal and survival of the fungi in various environments. These fungi do not have a sexual reproductive stage or it has not been observed, making their taxonomic classification challenging. They are commonly found in soil, decaying organic matter, and water, and some of them can cause diseases in humans, animals, and plants. Examples of mitosporic fungi include Aspergillus, Penicillium, and Fusarium species.
"Penicillium chrysogenum" is a species of filamentous fungi that is commonly found in the environment, particularly in soil and decaying vegetation. It is a member of the genus Penicillium, which includes several species that are known for their ability to produce penicillin, a group of antibiotics used to treat various bacterial infections.
"Penicillium chrysogenum" is one of the most important industrial producers of penicillin. It was originally identified as a separate species from "Penicillium notatum," which was the first species discovered to produce penicillin, but it is now considered to be a strain or variety of "Penicillium rubrum" or "Penicillium camemberti."
The fungus produces penicillin as a secondary metabolite, which means that it is not essential for the growth and development of the organism. Instead, penicillin is produced under certain conditions, such as nutrient limitation, to help the fungus compete with other microorganisms in its environment.
In addition to its medical importance, "Penicillium chrysogenum" also has industrial applications in the production of enzymes and other biomolecules. However, it can also cause food spoilage and allergic reactions in some individuals, so it is important to handle this organism with care.
Picolinic acid is not specifically classified as a medical term, but it is a type of organic compound that belongs to the class of molecules known as pyridinecarboxylic acids. These are carboxylic acids derived from pyridine by the substitution of a hydrogen atom with a carboxyl group.
Picolinic acid, specifically, is a pyridine derivative with a carboxyl group at the 2-position of the ring. It is naturally produced in the body and can be found in various tissues and fluids, including the brain, where it plays a role in the metabolism of amino acids, particularly tryptophan.
In addition to its physiological functions, picolinic acid has been studied for its potential therapeutic applications. For example, it has been shown to have antibacterial and antifungal properties, and may also play a role in heavy metal chelation and neuroprotection. However, more research is needed to fully understand the medical significance of this compound.
Lysine is an essential amino acid, which means that it cannot be synthesized by the human body and must be obtained through the diet. Its chemical formula is (2S)-2,6-diaminohexanoic acid. Lysine is necessary for the growth and maintenance of tissues in the body, and it plays a crucial role in the production of enzymes, hormones, and antibodies. It is also essential for the absorption of calcium and the formation of collagen, which is an important component of bones and connective tissue. Foods that are good sources of lysine include meat, poultry, fish, eggs, and dairy products.
Oxidoreductases acting on CH-NH group donors are a class of enzymes within the larger group of oxidoreductases, which are responsible for catalyzing oxidation-reduction reactions. Specifically, this subclass of enzymes acts on CH-NH group donors, where the CH-NH group is a chemical functional group consisting of a carbon atom (C) bonded to a nitrogen atom (N) via a single covalent bond.
These enzymes play a crucial role in various biological processes by transferring electrons from the CH-NH group donor to an acceptor molecule, which results in the oxidation of the donor and reduction of the acceptor. This process can lead to the formation or breakdown of chemical bonds, and plays a key role in metabolic pathways such as amino acid degradation and nitrogen fixation.
Examples of enzymes that fall within this class include:
* Amino oxidases, which catalyze the oxidative deamination of amino acids to produce alpha-keto acids, ammonia, and hydrogen peroxide.
* Transaminases, which transfer an amino group from one molecule to another, often in the process of amino acid biosynthesis or degradation.
* Amine oxidoreductases, which catalyze the oxidation of primary amines to aldehydes and secondary amines to ketones, with the concomitant reduction of molecular oxygen to hydrogen peroxide.
Proline is an organic compound that is classified as a non-essential amino acid, meaning it can be produced by the human body and does not need to be obtained through the diet. It is encoded in the genetic code as the codon CCU, CCC, CCA, or CCG. Proline is a cyclic amino acid, containing an unusual secondary amine group, which forms a ring structure with its carboxyl group.
In proteins, proline acts as a structural helix breaker, disrupting the alpha-helix structure and leading to the formation of turns and bends in the protein chain. This property is important for the proper folding and function of many proteins. Proline also plays a role in the stability of collagen, a major structural protein found in connective tissues such as tendons, ligaments, and skin.
In addition to its role in protein structure, proline has been implicated in various cellular processes, including signal transduction, apoptosis, and oxidative stress response. It is also a precursor for the synthesis of other biologically important compounds such as hydroxyproline, which is found in collagen and elastin, and glutamate, an excitatory neurotransmitter in the brain.