Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0027960 (mole)
 21,279 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The lactoperoxidase-catalyzed oxidation of glutathione (GSH) and thiocyanate (SCN-) was studied. Oxidation of SCN- was recorded by ultraviolet spectroscopy and by electron spin resonance (ESR). Consumption of GSH was measured by amperometric titration. One or two moles of GSH was oxidized per mole of H2O2 added, depending on the reaction conditions. Omission of SCN- prevented the oxidation of GSH. The oxidation of GSH required only catalytic amounts of SCN-, which was therefore recycled. Iodide (I-) could replace SCN-, while chloride or bromide were ineffective. The apparent Michaelis constant for SCN- was 17 microM. Oxidation of SCN- gave rise to two reactive intermediates, one stable and one unstable. The stable intermediate (-OSC. = N-(?)) decayed by a second-order reaction with a rate constant of 1.1 M-1 s-1. The decay of the unstable radical was very fast. The data (a) explain the short- and long-term antibacterial effects of lactoperoxidase-halide-H2O2 system, (b) point to possible deleterious effects due to glutathione depletion, (c) are of relevance for free radical diseases involving sulphur-centered free radicals, and (d) support previous observations on lipid peroxidation/halogenation in biological membranes, liposomes, and unsaturated fatty acids.
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PMID:Free radical generation and coupled thiol oxidation by lactoperoxidase/SCN-/H2O2. 132 2

2-Thiazoline-2-thiol is an antithyroid agent that strongly reduces thyroid hormone levels. Synthesis of these hormones is catalyzed in vivo by thyroid peroxidase. The interaction of this drug with molecular iodine and its effect on peroxidase activity were investigated. Iodine and 2-thiazoline-2-thiol form a complex of the charge transfer type of 1:1 stoichiometry characterized by a formation constant of 2,527 l.mole-1 at 20 degrees C. This drug was found to inhibit both horseradish peroxidase and lactoperoxidase (used as a model of thyroid peroxidase) in a competitive manner, giving inhibition constants of 5.7 mM and 0.13 mM, respectively. T3 and T4 levels were reduced significantly after a three-week administration of this drug to a group of 10 rats. Histological examination of the thyroid gland showed the presence of a cylindrical epithelium, which is indicative of hyperactivity of the gland. The results indicated that 2-thiazoline-2-thiol acts on both molecular iodine and thyroid peroxidase.
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PMID:Sites of action of 2-thiazoline-2-thiol on biogenesis of thyroid hormones. 138 Sep 99

The oxidation of NADPH catalyzed by horseradish peroxidase (HRP) and hydrogen peroxide (H2O2) is markedly increased by the presence of acetaminophen in a concentration-dependent manner. The oxidation follows pseudo-first order kinetics with respect to acetaminophen concentration. The product of the oxidation is enzymatically active NADP+. The stoichiometry of the reaction shows that 1.4 mol of NADPH are oxidized per mole of H2O2 added, and the addition of superoxide dismutase to the reaction mixture increases the ratio of NADPH oxidized:H2O2 consumed, which suggests formation of superoxide as a product. Monitoring cytochrome c reduction in the presence and absence of superoxide dismutase further suggests formation of superoxide. These results indicate that the HRP-H2O2 system oxidizes acetaminophen to the phenoxyl radical, N-acetyl-p-benzosemiquinone imime, which undergoes a rapid electron transfer reaction with NADPH. The NADP thus formed reacts with molecular oxygen to produce superoxide.
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PMID:Mechanism of acetaminophen-stimulated NADPH oxidation catalyzed by the peroxidase-H2O2 system. 167 96

We examined the influence of different staining techniques [(three-step immunoperoxidase technique (IP); alkaline phosphatase-anti-alkaline phosphatase technique (APAAP)] on the quantitative evaluation of Ki-67-labeled nuclei. We studied five melanocytic skin tumors. From each case, five parallel sections were prepared and stained using the peroxidase-antiperoxidase (PAP) technique (slide 1) and the APAAP technique once (slide 2). Slide 3 consisted of a single repetition of the APAAP technique, slide 4 was a double repetition, and slide 5 was a third repetition. We assessed the volume fraction (VV) of Ki-67-positive nuclei using computer-assisted image analysis. For each staining group, the mean value and standard deviation of VV were calculated. Comparing VV values obtained from the different staining groups we did not find a statistically significant difference between the IP and the various APAAP steps (Wilcoxon test, p = less than 0.05). However, the staining procedure influenced the quantitative results to some extent. The mean VV of the five staining groups ranged in our study from 0.10 to 0.17%, which is narrow compared with the overall variability among different cases (dermal melanocytic nevus, 0.01%; metastatic malignant melanoma, 0.43%). Therefore, we can state that for a rough evaluation of Ki-67-positive nuclei, the influence of different staining methods is negligible; for a subtle quantitative analysis, however, it would nevertheless be preferable to always apply the same staining technique.
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PMID:The influence of staining procedures on the assessment of cell proliferation as defined by the monoclonal antibody Ki-67. 170 Aug 83

Projections from the medial (MSO) and lateral (LSO) superior olivary nuclei to the inferior colliculus (IC) were examined in the mole. In each mole, Fluoro-Gold was injected into one IC and wheat germ-agglutinated horseradish peroxidase (WGA-HRP) into the other IC; most MSO neurons were double-labeled bilaterally, while most LSO neurons were single-labeled bilaterally. The results indicate that the bilateral projections from the MSO and LSO to the IC are mainly established by single MSO neurons with axon collaterals to the IC on both sides, and by two separate populations of LSO neurons with axons to the contralateral or ipsilateral IC.
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PMID:Differential organization of crossed and uncrossed projections from the superior olive to the inferior colliculus in the mole. 170 16

A mouse monoclonal antibody, FKH1, was produced to detect cytoplasmic melanoma-associated antigen. FKH1 was raised using cultured human melanoma cell line KHm-6 as immunogen. Reactivity of this antibody was assessed by immunohistochemical techniques. Positive reactions were seen against 5 human melanoma cell lines and cultured human epidermal melanocyte. It stained cytoplasm of melanoma cells in a diffuse and granular pattern with indirect immunofluorescence. Immunoelectron microscopy showed diffuse distribution of immuno-reactant in the cytoplasm of KHm-1 cells excluding melanosomes and other subcellular organelles. In immunoblotting, FKH1 bound with proteins having molecular weight of 71 kd and 55 kd extracted from KHm-6 cells. Reactivity against frozen and alcohol-fixed paraffin-embedded melanocytic tumors was also tested with indirect immunofluorescence or ABC (avidin biotin peroxidase complex) techniques. All cases of frozen sections from benign and malignant melanocytic tumors including 2 cases of amelanotic melanoma showed positive staining with FKH1. In fixed tissues, reactivity was 16/19 (84.2%) in malignant melanoma and 30/44 (68.2%) in other melanocytic tumors. FKH1 did not react against normal melanocytes, C-type nevus cell, intradermal nevus pigmentosus with neuroid structure and neurofibroma. It was demonstrated that FKH1 recognized proliferative melanocytes originated from melanoblast or melanoblastic nevoblast. FKH1 failed to stain normal human peripheral nerves and nonmelanocytic tumors except APUDoma and malignant Merkel cell tumor. In halo nevus, nevus cells were clearly distinguished from intermingling inflammatory cell infiltrate. It was suggested that FKH1 is a useful monoclonal antibody in diagnosing human malignant melanoma, particularly in evaluating tumor thickness of Breslow more precisely.
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PMID:[Mouse monoclonal antibody (FKH1) detecting human melanoma-associated antigens: production, partial characterization and immunohistochemical analysis]. 188 56

The mechanism of NADPH oxidation catalyzed by horse-radish peroxidase (HRP) and 2,4-diacetyl-[2H]heme-substituted horse-radish peroxidase (DHRP) was studied. The roles of the different H2O2/peroxidase compounds were examined by spectral studies. The oxidized NADPH species were identified using the superoxide dismutase effect and by measuring the stoichiometry between NADPH oxidized and H2O2 used. In the presence of a mediating molecule, like scopoletin, both enzymes acted via a similar mechanism, producing only NADP degrees, which in turn reacted with O2 producing O2-. Consequently H2O2 was completely regenerated in the presence of superoxide dismutase and partially regenerated in its absence. In the absence of a mediating molecule, the H2O2 complex of both enzymes (compound I) catalysed NADPH oxidation by single-electron transfer, producing NADP degrees; compound II of these enzymes catalyzed NADPH oxidation more slowly by a direct two-electron transfer, producing NADPH+. There were difference between HRP and DHRP. HRP compound II was produced by the oxidation of 1 mol NADPH/mole compound I, while DHRP compound II was formed by the spontaneous conversion of compound I to compound II. The NADPH oxidation catalyzed by DHRP compound I did not lead to the formation of compound II. When H2O2 was produced slowly by the glucose/glucose-oxidase system, compound II was never formed and a pure O2- adduct of DHRP (compound III) accumulated.
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PMID:Mechanism of NADPH oxidation catalyzed by horse-radish peroxidase and 2,4-diacetyl-[2H]heme-substituted horse-radish peroxidase. 193 47

The mole rat Spalax ehrenbergi is a fossorial rodent. Although its peripheral visual system--eye and optic nerve--is highly degenerated, it shows some sensitivity to light. However, in the usual sense, it is essentially blind. An auditory take-over of the visual lateral geniculate nucleus and at least part of the visual cortices was recently demonstrated. In order to visualize the retinal projections during ontogeny, we used an anterograde tracing technique, with monocular injection of wheat germ agglutinin-labeled horseradish peroxidase (WGA-HRP). In the newborn mole rat the retina projects to most of its normal targets as compared with seeing rodents, with bilateral projections to the suprachiasmatic nuclei, the dorsal and ventral lateral geniculate nuclei, the lateroposterior nuclei, the optic tract nuclei and the superior colliculi. During the course of ontogeny, the retinohypothalamic connection is stabilized but the main optic tract undergoes progressive degeneration. In adults, only a few retinal fibers enter the contralateral ventral lateral geniculate nucleus, the lateroposterior nucleus, the optic tract nucleus and the superior colliculus. No retinal fibers could be detected in the dorsal lateral geniculate nucleus. Thus, the retinofugal projections in the adult mole rat could explain its reduced sensitivity to light, whereas the complete degeneration of the retino-dorsal lateral geniculate nucleus projection could underlie the invasion of auditory input into this normally visual center.
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PMID:Retinal projections in the blind mole rat: a WGA-HRP tracing study of a natural degeneration. 202 63

Conformational changes of peroxidase and albumin in buffered solutions of propylthiouracil, an antithyroid drug, were evaluated by dialtometry and viscometry, showing that the structural alteration of peroxidase is related to the decoupling of the reactions which it catalyses. Thus, propylthiouracil probably inactivates the peroxidase by altering its structure. Equilibrium dialysis showed that albumin is the principle propylthiouracil-transporting protein in human serum. Propylthiouracil induces a conformational change in albumin when 1 mole of drug per mole of protein is bound, a structural alteration that can change the binding capability of other ligands.
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PMID:Conformational changes of peroxidase and albumin in solutions of propylthiouracil. 216 15

Anatomical organization of the central auditory system in the mole was studied at the lower brainstem levels. The cyto-, myelo-, and chemoarchitectures were examined in Nissl, myelin, and acetylcholinesterase stained materials, and then the origins of the ascending afferents to the inferior colliculus (IC) were identified by injecting wheatgerm agglutinin conjugated to horseradish peroxidase (WGA-HRP) into the unilateral IC and processing the tissue according to the standard retrograde tracing techniques. The results indicate that the auditory nuclei and pathways in the lower brainstem of the mole conform to the basic plan common to many other mammals. Nevertheless, several characteristic features are evidenced in the present study: (1) in the cochlear nucleus (CochN), granule cell fields are very large in both the ventral (VCN) and dorsal (DCN) nuclei; among several populations of neurons, fusiform cells in the DCN, multipolar cells in the VCN and DCN, and small spherical cells in the VCN project to the IC directly, (2) in the superior olivary complex (SOC), the medial nucleus (MSO) is well developed in comparison with that in the hedgehog, the opossum, the mouse, and the rat, although the general configuration of the SOC is similar to that in those mammals, most strikingly, the MSO projects to the IC bilaterally in the mole, and (3) the nuclei of the lateral lemniscus (NLL) show a great development and consist of three well-differentiated parts of the dorsal, intermediate, and ventral nuclei. The projections from these subnuclei to the IC conform to the basic mammalian plan.
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PMID:Auditory brainstem in the mole (Mogera): nuclear configurations and the projections to the inferior colliculus. 222 72


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