Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q86TM3 (cage)
 29,987 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Fifty-five patients (35 females and 20 males) were studied by noninvasive means 3.5-8.6 years after isolated mitral valve replacement with Models 103 and 104 Beall prostheses. History and physical exams by three physicians, complete hemograms, SMA 18, iron excretion rates, and coagulation profiles were performed. Additionally, electrocardiograms, echocardiograms, phonocardiograms, cardiac series, and high-speed cinefluorography of the prostheses were obtained. Valve wear was assessed by the disc/cage ratio measured from a "three-legged view" with magnification. At a mean duration of 5.85 years after operation, the entire group had a mean disc/cage ratio of operation, the entire group had a mean disc/cage ratio of 0.906 +/- 0.031 vs a normal value of 0.944 +/- 0.014. The group was mildly anemic and had a urinary iron loss that was 40 times normal. The lactic dehydrogenase (LDH) concentration was more than five times normal. The coagulation profiles were abnormal with respect to the bleeding and stypven times, antiheparin activity, fibrin degradation products, and megathrombocyte index. These abnormalities were unrelated to sex, degree of valve wear, and history of thromboembolism. Males were less anemic and had higher urine iron losses than females. Nine patients with severe valve wear (disc/cage ratio less than or equal to 0.87) were significantly more anemic with large urine iron losses and had elevated total bilirubin, serum glutamic oxaloacetic transaminase, and LDH concentrations (ninefold), when compared to nine patients with minimal wear (disc/cage ratio greater than or equal to 0.925). It is emphasized that the findings of a significant anemia, an LDH concentration greater than 1500 mU/ml, and a disc/cage ratio of less than 0.87 in a patient with an isolated Beall mitral valve prosthesis are indicators for the need to replace the prosthesis in the near future. Re-replacement is urged before significant clinical deterioration.
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PMID:Quantification of wear, hemolysis and coagulation deficits in patients with Beall mitral valves. 88 18

The present research describes studies which address the mechanism of prostacyclin (PGI2) and thromboxane A2 (TXA2) biosynthesis. In addition to prostaglandin H1 (PGH1), PGG2, PGH2, and PGH3, also 8-iso-PGH2, 13(S)-hydroxy-PGH2, and 15-keto-PGH2 were applied to determine the substrate specificities and kinetics of prostacyclin and thromboxane synthase in more detail. Human platelet thromboxane synthase converted PGH1, 8-iso-PGH2, 13(S)-hydroxy-PGH2 and 15-keto-PGH2 into the corresponding heptadecanoic acid (C17) plus malondialdehyde, whereas the thromboxane derivative was formed only from PGG2, PGH2, and PGH3 together with the corresponding C17 metabolite and malondialdehyde in a 1:1:1 ratio. In contrast, PGG2, PGH2, 13(S)-hydroxy-PGH2, 15-keto-PGH2 and PGH3 were almost completely isomerized to the corresponding prostacyclin derivative by bovine aortic prostacyclin synthase, whereas PGH1 and 8-iso-PGH2 only produced the corresponding C17 hydroxy acid plus malondialdehyde. Isotope-labeling experiments with [5,6,8,9,11,12,14,15-2H]PGH2 revealed complete retention of label and no isotope effect in the course of thromboxane biosynthesis, but the loss of one 2H atom at C-6 with an isotope effect of 1.20 during PGI2 formation. Prostacyclin and thromboxane synthase bind both 9,11-epoxymethano-PGF2 alpha and 11,9-epoxymethano-PGF2 alpha at the heme iron, but according to their difference spectra in opposite ways with respect to the 9- and 11-position. In agreement with published model studies, a cage radical mechanism is proposed for both enzymes according to which the initial radical process is terminated through oxidation of carbon-centered radicals by the iron-sulfur catalytic site, followed by ionic rearrangement to PGI2 or TXA2. Various Fe(III) model compounds as well as liver microsomes or cytochrome P-450CAM can also form small amounts of PGI2 and TXA2, but mainly yield 12(S)-hydroxy-5,8,10-heptadecatrienoic acid plus malondialdehyde probably by a radical fragmentation pathway.
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PMID:On the mechanism of prostacyclin and thromboxane A2 biosynthesis. 249 46

The effect of age on hematopoiesis was studied in young (six-month) and old (24-month) C57BL/6 mice. In addition, studies were performed on very old (42-month) mice, housed either singly or in groups of five animals per cage. Although a reduction in hematocrit was found in the older mice, red cell mass was normal in both old and very old single-caged mice. A detailed evaluation of erythropoiesis that included plasma- and erythron-iron turnover (PIT and EIT), red cell survival, and quantitation of the marrow erythroid progenitor and differentiated cells demonstrated no age-related change in single-caged animals. Similarly, quantitation of marrow myeloid precursors was identical in these groups. These results indicate that no age-related change in basal hematopoiesis can be demonstrated even in animals approaching maximal life expectancy. When very old mice were routinely housed in groups of five per cage, however, a decrease in hematocrit was found which was accompanied by significant alterations in hematopoiesis, including reductions in total differentiated erythroid cells, erythroid burst-forming units (BFU-E), erythroid colony-forming units (CFU-E), and colony-forming-unit culture (CFU-C) levels. It is likely that in very old animals, group housing constitutes a sufficient stress to compromise hematopoiesis. These findings indicate that basal hematopoiesis is unaltered by aging, although the bone marrow's reserve capacity is markedly compromised.
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PMID:Evaluation of the effect of age on hematopoiesis in the C57BL/6 mouse. 375 34

This study was designed to determine the ACTH-corticosterone response to two types of stress in relation to the daily rhythm of food and water intake in the iron-deficient rat. Rats were fed diets containing 2, 10 or 50 mg iron/kg diet between weaning at 21 days and the stress experiments at 38 or 42 days of age. The two iron-deficient diets (2 and 10 mg iron/kg) resulted in mean hemoglobin concentrations of about 6.0 and 8.5 g/dl, respectively, in contrast to about 12.5 g/dl in the control group receiving 50 mg iron/kg diet. Food and water consumption followed the normal nocturnal pattern, irrespective of iron intake. ACTH and corticosterone showed the normal baseline peaks at the 2000 hour lights-out point in all groups. Responses to handling and placement into another cage were similar in most respects but suggested an inappropriately low corticosterone response despite high ACTH values only at the 2000 hour point. However, there was no evidence of similar differences in response to the more potent stress of an i.p. injection of histamine 1 mg/100 g body weight. In contrast to the reports of more clear-cut effects of iron deficiency on norepinephrine, the changes in ACTH and corticosterone response to stress seem relatively modest.
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PMID:The pituitary-adrenal response to stress in the iron-deficient rat. 609 Jun 19

The complex of cytochrome c oxidase with NO and azide has been studied by EPR at 9.2 and 35 GHz. This complex which shows delta ms = 2 EPR triplet and strong anisotropic signals, due to the interaction of cytochrome a2+3 X NO (S = 1/2) and Cu2+B (S = 1/2), is photodissociable . Its action spectrum is similar to that of cytochrome a2+3 X NO with bands at 430, 560 and 595 nm, but shows an additional band in the near ultraviolet region. The quantum yield of the photodissociation process of cytochrome a2+3 X NO in the metal pair appears to depend on the redox state of CuB. When the photolysed sample was warmed to 77 K, a complex was observed with the EPR parameters of cytochrome a3+3 - N-3 - Cu1 +B (S = 1/2). This process of electron and ligand transfer can be reversed by heating the sample to 220 K. It is suggested that in the triplet species azide is bound to Cu2+B whereas NO is bridged between Cu2+B and the haem iron of the cytochrome a2+3. The complex has a triplet ground state and a singlet excited state with an exchange interaction J = -7.1 cm-1 between both spins. The anisotropy in the EPR spectra is mainly due to a magnetic dipole-dipole interaction between cytochrome a2+3 X NO and Cu2+B. From simulations of the triplet EPR spectra obtained at 9 and 35 GHz, a value for the distance between the nitroxide radical and Cu2+B of 0.33 nm was found. A model of the NO binding in the cytochrome a3-Cu pair shows a distance between the haem iron of cytochrome a3 and CuB of 0.45 nm. It is concluded that the cytochrome a3-CuB pair forms a cage in which the dioxygen molecule is bidentate coordinated to the two metals during the catalytic reaction.
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PMID:The cytochrome c oxidase-azide-nitric oxide complex as a model for the oxygen-binding site. 632 19

A protein-encaged superparamagnetic iron oxide has been developed and characterized by using horse spleen apoferritin as a novel bioreactive environment. The roughly spherical magnetoferritin molecules, 120 A in diameter, are composed of a monocrystalline maghemite or magnetite core 73 A +/- 14 in diameter. Except for the additional presence of iron-rich molecules of higher molecular weight, the appearance and molecular weight (450 kd) of magnetoferritin are identical to that of natural ferritin; the molecules are externally indistinguishable from their precursor, with a pI (isoelectric point) in the range 4.3-4.6. The measured magnetic moment of the superparamagnetic cores is 13,200 Bohr magnetons per molecule, with T1 and T2 relaxivities (r1 and r2) of 8 and 175 L.mmol-1 (Fe).sec-1, respectively, at body temperature and clinical field strengths. The unusually high r2/r1 ratio of 22 is thought to arise from ideal core composition, with no evidence of crystalline paramagnetic inclusions. T2 relaxation enhancement can be well correlated to the field-dependent molecular magnetization, as given by the Langevin magnetization function, raised to a power in the range 1.4-1.6. With its nanodimensional biomimetic protein cage as a rigid, convenient matrix for complexing a plethora of bioactive substances, magnetoferritin may provide a novel template for specific targeting of selected cellular sites.
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PMID:Magnetoferritin: characterization of a novel superparamagnetic MR contrast agent. 780 66

Between 1897 and 1902 the economist and sociologist Max Weber from Heidelberg suffered from a severe depressive crisis with multiple recurrences of its symptomatology in the following years. The biographic background of the disease process is examined. Questions regarding the specific diagnosis are discussed. Furthermore, his work shows that Weber was indirectly deeply concerned with the cultural, historical and social background conditions of depressive experience and behavior in the context of his study on Protestantic Ethics and the Spirit of Capitalism. Weber's definition of modern society as an iron cage, determined by Occidental Rationalism, shows that this cultural background demands a great amount of role conformity from the individual. Weber's theoretical approach should spark interest in the current psychopathological discussion of the characteristic structural features of a depressed personality.
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PMID:[Max Weber's illness--sociologic aspects of the depressive structure]. 831 27

The kinetics of tert-butyl isocyanide binding to the heme protein horseradish peroxidase (HRP) at 22 degrees C was examined on all time scales, from minutes to picoseconds, in aqueous borate buffer at pH 9.08. Unlike myoglobin (Mb) or hemoglobin, HRP shows two bimolecular ligand binding processes. For comparison, binding of the same ligand with Mb was measured under identical conditions. Ligand entry into the protein from the solvent in a mixing experiment is extremely slow in HRP: the bimolecular association constant is 0.04 M-1 s-1, while in Mb it is 4 x 10(3) M-1 s-1. Surprisingly, in view of that difference, picosecond and nanosecond photolyses reveal that once the ligand has reached the iron(II) site there is no difference in cage return or escape from the protein. The rate for the fastest cage return (from the contact pair) is close to 6 x 10(10) s-1 in both proteins. The rates of escape from the contact pair to form a secondary protein-caged pair are also similar: for Mb, 10 x 10(10) s-1, and for HRP, 8.5 x 10(10) s-1. The rate of rebinding from the protein-separated cage is near 4 x 10(6) s-1 in both proteins, and the rate of escape from protein to solvent is close to 3.7 x 10(6) s-1 in both. The difference between the two proteins lies in the low-millisecond time domain. After flash photolysis of HRP, there is a concentration-dependent recombination not seen in mixing experiments. This bimolecular rate constant varies slightly for different HRP preparations, being 2.6 x 10(4) or 4.0 x 10(4) M-1 s-1 in two cases, both of which are much faster than is observed in mixing experiments, namely, 0.04 M-1 s-1. In Mb, photolysis and mixing experiments consistently give the same combination rate, which is somewhat slower than the faster part of the HRP recombination. Similar measurements for the smaller ligand methyl isocyanide revealed no anomalous behavior. The interpretation proposed involves tertiary relaxation after ligand escape, which is significant in blocking the return of the large t-BuNC, but has no apparent effect on smaller ligands. Thus, HRP-t-BuNC reveals in dramatic fashion a phenomenon merely hinted at in earlier work involving the T-state binding kinetics of hemoglobin.
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PMID:Evidence for a slow tertiary relaxation in the reaction of tert-butyl isocyanide with horseradish peroxidase. 863 80

The influence of plasma corticosterone concentration on serotonin (5-HT) turnover in the dorsal hippocampus was investigated. The experiments were performed in freely moving male Wistar rats in their home cage. Blood samples were taken via a permanent jugular vein catheter to determine plasma corticosterone levels. Extracellular levels of 5-HT and its metabolite 5-hydroxy-indole acetic acid (5-HIAA) were measured using in vivo microdialysis. The rats received an intravenous (i.v.) infusion of the steroid synthesis-inhibitor metyrapone (150 mg/kg/ml) in order to manipulate circulating corticosterone levels. Three hours later, the monoamine oxidase inhibitor pargyline (15 mg/kg/2 ml i.v.) was administered to produce an accumulation of extracellular 5-HT. Pargyline administration led to a four fold increase in 5-HT levels, while reducing 5-HIAA by 45%. Metyrapone pretreatment blocked the pargyline-induced rise in plasma corticosterone to baseline levels and diminished the pargyline-induced increase in 5-HT, without affecting 5-HIAA levels. Thus, the data suggest that a decrease in availability of corticosterone for its receptors by metyrapone diminished the 5-HT synthesis rate. Since plasma corticosterone levels during this blockade are still low, it is assumed that brain glucocorticoid receptor occupation is reduced, while mineralocorticoid receptors are still substantially occupied. Therefore the present results support the hypothesis that corticosterone through glucocorticoid receptor activation enhances 5-HT synthesis rate and release in the dorsal hippocampus.
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PMID:Blockade of corticosterone synthesis reduces serotonin turnover in the dorsal hippocampus of the rat as measured by microdialysis. 893 65

A multimeric protein that behaves functionally as an authentic ferritin has been isolated from the Gram-positive bacterium Listeria innocua. The purified protein has a molecular mass of about 240,000 Da and is composed of a single type of subunit (18,000 Da). L. innocua ferritin is able to oxidize and sequester about 500 iron atoms inside the protein cage. The primary structure reveals a high similarity to the DNA-binding proteins designated Dps. Among the proven ferritins, the most similar sequences are those of mammalian L chains that appear to share with L. innocua ferritin the negatively charged amino acids corresponding to the iron nucleation site. In L. innocua ferritin, an additional aspartyl residue may provide a strong complexing capacity that renders the iron oxidation and incorporation processes extremely efficient. This study provides the first experimental evidence for the existence of a non-heme bacterial ferritin that is related to Dps proteins, a finding that lends support to the recent suggestion of a common evolutionary origin of these two protein families.
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PMID:A novel non-heme iron-binding ferritin related to the DNA-binding proteins of the Dps family in Listeria innocua. 901 63


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