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Query: UNIPROT:P50583 (
asymmetrical
)
12,197
document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)
Two cases of spontaneous cerebral ventriculostium are presented. The first case is that of a 3 year-old girl with a thumb-sized soft scalp tumor of the occipital region (dural hypertrophy) and hydroencephalodysplasia (Picaza). PVG revealed noncommunicating hydrocephalus with
asymmetrical
deformity of the lateral ventricle and agenesis of corpus callosum (Fig. 1). Ventriculoatrial shunt was performed. Three years passed under the useful life when she readmitted to our clinic complaining headache, nausea and vomiting. On the first hospital day she fell into respiratory arrest accompanied with coma after the tonic convulsion, and eventually, she died on the fourth hospital day. Postmortem examination revealed spontaneous cerebral ventriculostium which communicated with the posteromedial trigone of the left lateral ventricle (Fig. 3). Combined other malformations such as dysgenesis of the corpus callosum and only one anterior cerebral artery, etc. were found. The second case is that of a young adult, a 22 year-old male with rapidly progressing intracranial hypertension. PVG revealed marked dilatation of the lateral and the third ventricle, non-filling of the aqueduct and spontaneous cerebral ventriculostium which communicated with the posterior part of the third ventricle (Fig. 4). And insidiously he fell into akinetic mutism. After suboccipital exploratory craniotomy and ventriculo-peritoneal shunt akinetic mutism improved gradually, and he was discharged on foot after 7 months.
PEG
performed on June 8, 1973, showed no evidence of aqueduct obstruction and injected air passed from the fourth ventricle to the third one smoothly. He lives on now under a useful condition. These 2 cases are the first report on literatures in Japan, but presumably there must be many other cases. Since W. H. Sweet reported his own two cases of spontaneous cerebral ventriculostium on 1940, more than thirty cases have been published on literatures. However, there are found various expressions to describe the same condition (Table 1). We would like to propose that the most suitable expression is "ventriculostium" not only in deference to the originality of W. H. Sweet but also not to confuse this pathogenetic state with other similar conditions. The author's next interest is the chronological fact that from W. H. Sweet (1940) to A. Torkildsen (1948), all but one ostiums reported situated at the posteromedial trigone of the lateral ventricle, whereas after A. Torkildsen, they were found at the posterior part of the third ventricle in many cases. The reason is unknown. It would appear that three main conditions are necessary for the development of ventricluostium just beneath the tentorium. The first, there must be increased pressure within the lateral or the third ventricle. The second essential feature is the lack of any large space occupying lesion in the the infratentorial space. The third, there must be wider space between the tentorial incisura and the brain stem.
...
PMID:[Spontaneous cerebral ventriculostium (author's transl)]. 94 70
A high affinity calcium-binding protein has recently been purified from the adrenal medulla (Kuo, I.C.Y., and Coffee, C.J. (1976) J. Biol. Chem. 251, 1603-1609). This protein is closely related in its chemical and physical properties to troponin-C (TN-C) of muscle tissue. Further examination of the adrenal medulla protein indicates that the removal of calcium is accompanied by a marked change in the conformation. This change in structure is similar, if not identical, to the calcium-dependent conformational change which has been described for skeletal muscle TN-C (Murray, A.C., and Kay, C.M. (1972) Biochemistry 11, 2622). The far ultraviolet circular dichroism spectrum of native adrenal medulla calcium-binding protein (AM-CBP) shows characteristic helical ellipticity bands at 222 and 207 nm. The helical content, as estimated from these data, is between 40 and 45%. Removal of calcium is accompanied by a change in ellipticity which corresponds to a decrease from 40 to 20% in the helical content. The near-ultraviolet circular dichroism spectrum shows negative dichroic bands at 262 and 268 nm which are characteristic of phenylalanine. These bands are relatively insensitive to changes in the calcium ion concentration. Sedimentation velocity studies likewise are indicative of a calcium-dependent structural alteration. The sedimentation coefficient of the native protein was observed to be 1.89 S. Similar measurements performed in the presence of 3 mM
ethylene glycol
bis(beta-aminoethyl ether) N,N, N', N'-tetraacetic acid (EGTA) gave a sedimentation coefficient of 1.50 S. The molecular weight, as determined by sedimentation equilibrium studies, was 16,000 regardless of whether the measurements were made in the presence of CaCl2 or EGTA. From the elution properties of AM-CBP on Sephadex G-100, the Stokes radius was observed to be 19.8 A in the presence of calcium and 21.9 A in the presence of EGTA. All of these changes which were induced by the addition of EGTA were completely reversible by the readdition of excess CaCl2. These data suggest that the removal of calcium from AM-CBP is accompanied by a pronounced conformational change which occurs without a molecular weight change. The decreased sedimentation coefficient, the increased Stokes radius, and the reduced helical content, which are observed for the apoprotein, indicate that removal of calcium results in a transformation from a compact symmetrical structure to one that is less ordered and more
asymmetrical
.
...
PMID:Bovine adrenal medulla troponin-C. Demonstration of a calcium-dependent conformational change. 97 71
Low concentrations of methanol, 2-propanol and
ethylene glycol
increase the asymmetry of the flagellar waveforms ad the turning rate of both live sperm and potentially symmetrical sperm reactivated with 1 mM-MgATP2-, while at the same time causing a decrease in the heat frequency. Similar effects are observed if the solvents are added to preparations of potentially symmetrical sperm reactivated in the presence of 1 mM free Ca2+, or to potentially
asymmetrical
sperm reactivated without added Ca2+, A second group of solvents, N,N-dimethylformamide, formamide and p-dioxane, also decrease the flagellar beat frequency, but have the opposite effect on symmetry, reducing the asymmetry of the waveforms and the turning rate of potentially symmetrical sperm reactivated in the presence of 1 mM free Ca2+. These effects of solvents are all reversible within about 5 min after initial exposure to solvent. Higher concentrations of methanol and 2-propanol (above approximately 5 and 0.8 mole %, respectively) induce quiescence in potentially
asymmetrical
sperm reactivated with concentrations of MgATP2- ranging from 10 microM to 1 mM. The quiescent flagella initially assume a bent form very similar to that seen in Ca2+-induced quiescence, and show a subsequent time-dependent distortion of the initial bent from with eventual disintegration and splitting off of bundles of microtubules. Dimethylformamide, formamide and dioxane have almost no effect on the intrinsic asymmetry of potentially
asymmetrical
sperm reactivated in the absence of added Ca2+, but addition of these solvents to potentially
asymmetrical
sperm that have been induced to become quiescent by addition of 0.1 mM free Ca2+ causes the sperm to resume swimming with flagellar waveforms that are substantially more symmetrical that those of the starting preparation before the addition of Ca2+. Mild digestion with trypsin of reactivated sperm that have been induced either to beat asymmetrically or to become quiescent by addition of methanol causes a gradual appearance of symmetrical flagellar beating, as in the case of Ca2+-induced quiescence. The flagellar beat frequency, however, remains low, at about 20 Hz. The results suggest that the solvents either mimic or block the action of CA2+ by interaction with a Ca2+-dependent regulatory protein, and may also induce alteration in the rate constants of dynein ATPase.
...
PMID:Effects of organic solvents on flagellar asymmetry and quiescence in sea urchin sperm. 707 22
Four types of hydrophilic gel microcapsules containing water have been prepared by an interfacial polymerization method. Each type of microcapsules has membranes of different compositions. Using three kinds of monomers, N,N-dimethylacrylamide (DMAAm), 4-aminomethylstyrene (AmSt), and N,N-dimethylaminopropylacrylamide (DMAPAA), two types of water-soluble copolymers with different compositions having primary and tertiary amino groups were obtained. Two more types of copolymers were synthesized by copolymerization of alpha-acryloxy-omega-methoxy-poly(
ethylene glycol
) (a-
PEG
) with the above two kinds of monomer mixtures. These copolymers were polymerized with terephthaloyldichloride at the water/oil interface to prepare four types of microcapsules containing water. By electrophoretic mobility measurements of these microcapsules and the analyses of the data, it was found that the surface layer of the microcapsule membranes were composed of two sublayers, each of which has different charge density and softness. The outer sublayer was negatively charged and inner sublayer was positively charged. By PEGylation, the charge density in the outer sublayer decreased, while that in the inner sublayer was not affected. Also, the surface layer became softer by PEGylation. The effects of membrane composition upon the swellability of the microcapsule membrane were studied. It was found that the
asymmetrical
structure of the microcapsule membranes causes the nonuniform distribution of charges and then the swellability of the microcapsule membrane changes depending on the permittivity of the dispersing medium. Copyright 1999 Academic Press.
...
PMID:Two-Layer Structure of Microcapsule Membrane as Predicted from Electrophoretic Studies. 1048 2
A new double-seeded insert (DSI) technique is described for culture of branchial epithelial preparations from freshwater rainbow trout on filter supports. DSI epithelia contain both pavement cells and mitochondria-rich (MR) cells (15.7+/-2.5 % of total cell numbers). MR cells occur singly or in clusters, are voluminous, open apically to the 'external environment' and exhibit ultrastructural characteristics similar to those found in the 'chloride cells' of freshwater fish gills. After 6-9 days in culture with Leibovitz's L-15 medium on both surfaces (symmetrical conditions), transepithelial resistance (TER) stabilized at values as high as 34 k capomega cm(2), indicative of electrically 'tight' epithelia. The density of MR cells, the surface area of their clusters and transepithelial potential (TEP; up to +8 mV basolateral positive, mean +1.9+/-0.2 mV) were all positively correlated with TER. In contrast, preparations cultured using an earlier single-seeded insert (SSI) technique contained only pavement cells and exhibited a negligible TEP under symmetrical conditions. Na(+)/K(+)-ATPase activities of DSI preparations were comparable with those in gill filaments, but did not differ from those of SSI epithelia. Replacement of the apical medium with fresh water to mimic the in vivo situation (
asymmetrical
conditions) induced a negative TEP (-6 to -15 mV) and increased permeability to the paracellular marker
PEG
-4000. Under symmetrical conditions, unidirectional Na(+) and Cl(-) fluxes were in balance, and there was no active transport by the Ussing flux ratio criterion. Under
asymmetrical
conditions, there were large effluxes, small influxes and evidence for active Cl(-) uptake and Na(+) extrusion. Unidirectional Ca(2+) fluxes were only 0.5-1.0 % of Na(+) and Cl(-) fluxes; active net Ca(2+) uptake occurred under symmetrical conditions and active net extrusion under
asymmetrical
conditions. Thus, DSI epithelia exhibit some of the features of the intact gill, but improvements in culture conditions are needed before the MR cells will function as true freshwater 'chloride cells'.
...
PMID:Transport properties of cultured branchial epithelia from freshwater rainbow trout: a novel preparation with mitochondria-rich cells. 1076 15
The physiological effects of ovine prolactin (oPRL) and recombinant rainbow trout prolactin (rbtPRL) on cultured gill epithelia derived from freshwater rainbow trout were assessed. Epithelia composed of either pavement cells only (single seeded inserts, SSI) or both pavement and mitochondria-rich cells (double seeded inserts, DSI) were cultured in media, supplemented with doses of oPRL ranging from 10 to 100 ng/ml. Under symmetrical culture conditions (L15 media apical/L15 media basolateral), oPRL had no effect on transepithelial resistance, paracellular permeability (assessed with
PEG
-4000), or Na(+) and Cl(-) transport across both preparations of cultured gill epithelia. Under
asymmetrical
conditions (freshwater apical/L15 media basolateral), SSI epithelia treated with oPRL (10 and 50 ng/ml), in comparison to comparably treated epithelia receiving no oPRL, exhibited a greater increase in the transepithelial resistance, particularly during the first 12h of freshwater exposure, no difference in paracellular permeability and Na(+)-K(+)-ATPase activity, and lowered net Na(+) flux rates (i.e., reduced basolateral to apical loss rates). These reflected reduced unidirectional efflux rates. The PRL effect appeared to be mainly a reduction in transcellular permeability. SSI epithelia treated with rbtPRL (10 ng/ml) exhibited similar patterns of response to those treated with oPRL. Na(+)-K(+)-ATPase activity increased in DSI epithelia treated with oPRL; however, oPRL did not stimulate ion uptake across either SSI or DSI epithelial preparations. The data demonstrated that, as the sole hormone supplement for cultured gill epithelia, PRL did not promote active ion uptake. However, the observed PRL-induced alterations in cultured gill epithelial physiology were consistent with the in vivo actions of PRL on the gills of freshwater teleost fish.
...
PMID:Prolactin effects on cultured pavement cell epithelia and pavement cell plus mitochondria-rich cell epithelia from freshwater rainbow trout gills. 1227 Jul 87
A solution-phase procedure using an orthogonal protection scheme was developed for the synthesis of a novel family of multi-pegylating reagents. The procedure was exemplified by the synthesis of bis- and tris-pegylating reagents prepared by stepwise insertion of the poly(
ethylene glycol
) units thereby enabling the preparation of both symmetrical and
asymmetrical
pegylating reagents. Asymmetrical pegylation and tris-pegylation of peptides and proteins introduces new variables for use in the optimization of pegylated peptides and proteins. These reagents are ideally suited for conjugation to peptides and proteins as they possess a required functional group and will be useful intermediates for the synthesis of a new generation of pegylated products. Tris-pegylation can also provide more effective protection from proteolysis by shielding the protein surface from approaching macromolecules. To illustrate this potential, conditions were developed for the successful coupling of the tris-pegylating reagent to a model pentapeptide.
...
PMID:Synthesis of symmetrically and asymmetrically branched pegylating reagents. 1500 29
Broadband dielectric measurements for 65 wt %
ethylene glycol
oligomer (EGO)-water mixtures with one to six repeat units of EGO molecules were performed in the frequency range of 10 microHz-10 GHz and the temperature range of 128-298 K. In the case of the water-EGO mixtures with one and two repeat units of the EGO molecule (small EGO), the shape of the dielectric loss peak of the primary process is
asymmetrical
about the logarithm of the frequency of maximum loss above the crossover temperature, T(C). The asymmetric process continues to the alpha process at a low frequency, and an additional beta process appears in the frequency range higher than that of the alpha process below T(C). In contrast, the water-EGO mixtures with three or more repeat units of the EGO molecule (large EGO) show a broad and symmetrical loss peak of the primary process above T(C). The symmetric process continues to the beta process, and an additional alpha process appears in the frequency range lower than that of the beta process below T(C). These different scenarios of the alpha-beta separation related to the shape of the loss peak above T(C) are a result of the difference in the cooperative motion of water and solute molecules. The solute and water molecules move cooperatively in the small EGO-water mixtures above T(C), and this cooperative motion leads to the asymmetric loss peak above T(C) and the alpha process below T(C). For the large EGO-water mixtures, the spatially restricted motion of water confined by solute molecules leads to the symmetric loss peak above T(C) and the beta process below T(C).
...
PMID:Dielectric study of the alpha and beta processes in supercooled ethylene glycol oligomer-water mixtures. 1547 3
A non-disintegrating polymeric capsule system, in which asymmetric membrane offers an improved osmotic effect, was used to deliver poorly water-soluble drugs in a control manner. The capsule wall membrane was made by a phase inversion process, in which asymmetric membrane was formed on stainless-steel mold pins by dipping the mold pins into a coating solution containing a polymeric material followed by dipping into a quench solution. This study evaluates the influence of coating formulation that was cellulose acetate (CA), ethylcellulose (EC), and plasticizer (glycerin and triethyl citrate). Results show capsule that made by CA with glycerin (formulation A), which appear in asymmetric structure and are able to release chlorpheniramine maleate (CM) in significant percentage. Two poorly water-soluble drugs of felodipine (FL) and nifedipine (NF) were selected as the model drug to demonstrate how the controlled release characteristics can be manipulated by the design of polymeric capsules with an asymmetric membrane and core formulations. Results show that sodium lauryl sulfate (SLS) is able to promote the release of FL from polymeric capsules prepared with CA with
asymmetrical
membrane. The addition of solubilizer, including RH40, PVP K-17, and
PEG
4000 could enhance the release of FL but with an extent not being related to its solubility. Based on these results, influence of core formulation variables, including the viscosity and added amount of hydroxypropyl methylcellulose (HPMC), the added amount of SLS, and drug loading were examined on the release of NF. It was found that HPMC of 50 cps was suitable to be a thickening agent and both added amount of HPMC and SLS showed a comparable and profoundly positive effect, whereas NF loading had no influence on the drug release percent and rate. There existed a synergistic interaction between HPMC and SLS on the release percent and rate.
...
PMID:Asymmetric membrane capsules for delivery of poorly water-soluble drugs by osmotic effects. 1588 36
Diadenosine tetraphosphate (Ap4A) hydrolase (EC 3.6.1.41) hydrolyzes Ap4A symmetrically in prokaryotes. It plays a potential role in organisms by regulating the concentration of Ap4A in vivo. To date, no three-dimensional structures of proteins with significant sequence homology to this protein have been determined. The 31.3 kDa
Ap4A hydrolase
from Shigella flexneri 2a has been cloned, expressed and purified using an Escherichia coli expression system. Crystals of
Ap4A hydrolase
have been obtained by the hanging-drop technique at 291 K using
PEG
550 MME as precipitant.
Ap4A hydrolase
crystals diffract X-rays to 3.26 A and belong to space group P2(1), with unit-cell parameters a = 118.9, b = 54.6, c = 128.5 A, beta = 95.7 degrees.
...
PMID:Preparation, crystallization and preliminary X-ray crystallographic studies of diadenosine tetraphosphate hydrolase from Shigella flexneri 2a. 1651 Dec 39
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