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At least 1,009 records · Page 56Linked to original sources
PubMed2003

Metabolism of the soy isoflavones daidzein, genistein and glycitein in human subjects. Identification of new metabolites having an intact isoflavonoid skeleton.

Epidemiological studies have associated high soy intake with a lowered risk for certain hormone-dependent diseases. Soy and soy foods are rich sources of isoflavones, which have been shown to possess several biological activities. In this study, the metabolism of soy isoflavones daidzein, genistein and glycitein was investigated in human subjects. The aim was to find and identify urinary phase I metabolites of isoflavones, which have an intact isoflavonoid skeleton, and which might possess some bioactivity. Six volunteers included three soy bars per day into their normal western diet for a 2-week period. Daily urine samples were collected before, and after the supplementation period. Urine samples were hydrolyzed with Helix pomatia, extracted with diethyl ether, purified with Sephadex LH-20 chromatography, and analyzed as trimethylsilyl derivatives using gas chromatography-mass spectrometry (GC-MS). The structures of the isoflavone metabolites were identified using authentic reference compounds. The metabolites, for which authentic reference compounds were not available, were identified by the interpretation of mass spectra. Several new isoflavone metabolites were identified, and the presence of previously reported metabolites confirmed. The metabolic pathways of daidzein, genistein and glycitein are presented on the basis of the identification of the metabolites in human urine after soy supplementation.

Adult↗
PubMed2006

Homeotic transformations of the axial skeleton of YY1 mutant mice and genetic interaction with the Polycomb group gene Ring1/Ring1A.

Polycomb group (PcG) proteins participate in the maintenance of transcriptionally repressed state of genes relevant to cell differentiation. Here, we show anterior homeotic transformations of the axial skeleton of YY1(+/-) mice. We find that the penetrance of some of these alterations was reduced in mice that are deficient in the class II PcG gene Ring1/Ring1A, indicating a genetic interaction between those two genes. Further support for this interaction is an abnormal anterior eye formation in Ring1-deficient mice, which is enhanced in compound YY1(+/-)Ring1(-/-) mice. In addition, YY1 forms complexes with Ring1 and other class II PcG proteins such as Rnf2 and Bmi1 in GST pull down experiments in transfected cells. These findings provide evidence for a PcG function for YY1 in vertebrates.

Animals↗
PubMed2005

Distraction osteogenesis in the craniofacial skeleton.

Bone deficiency in the craniofacial skeleton has posed a challenge to craniomaxillofacial surgeons for many decades. Sliding osteotomies and bone grafting have been traditional staples for correcting bone deficiency. In recent years, especially with the advent of newer devices, mechanically induced growth of bone and soft tissue has be-come a major tool in the correction of bony deficiency of the skull and face. In this article, the authors discuss the physiology and technique of distraction osteogenesis, or mechanically induced growth,for the correction of congenital and acquired facial deformities.

Adolescent↗
PubMed2005

Biosynthesis of the hyperforin skeleton in Hypericum calycinum cell cultures.

Hyperforin is an important antidepressant constituent of Hypericum perforatum (St. John's wort). Cell cultures of the related species H. calycinum were found to contain the homologue adhyperforin and to a low extent hyperforin, when grown in BDS medium in the dark. Adhyperforin formation paralleled cell culture growth. Cell-free extracts from the cell cultures contained isobutyrophenone synthase activity catalyzing the condensation of isobutyryl-CoA with three molecules of malonyl-CoA to give phlorisobutyrophenone, i.e. the hyperforin skeleton. The formation of the hyperforins during cell culture growth was preceded by an increase in isobutyrophenone synthase activity. The cell cultures also contained benzophenone synthase and chalcone synthase activities which are involved in xanthone and flavonoid biosyntheses, respectively. The three type III polyketide synthases were separated by anion exchange chromatography.

Acyltransferases↗
PubMed2005

Flavonols and an indole alkaloid skeleton bearing identical acylated glycosidic groups from yellow petals of Papaver nudicaule.

From yellow petals of Iceland poppy, besides the known flavonoid gossypitrin, seven kaempferol derivatives were isolated. In addition to kaempferol 3-O-beta-sophoroside and kaempferol 3-O-beta-sophoroside-7-O-beta-glucoside, known from other plants, the mono- and dimalonyl conjugates of the latter were identified by MS and NMR spectroscopy. Structure analyses of a set of co-occurring pigments, the nudicaulins, revealed that they have the identical acylated glycoside moieties attached to a pentacyclic indole alkaloid skeleton for which the structure of 19-(4-hydroxyphenyl)-10H-1,10-ethenochromeno[2,3-b]indole-6,8,18-triol was deduced from MS and NMR as well as chemical and chiroptical methods.

Alkaloids↗
PubMed2006

Salvidorol, a nor-abietane diterpene with a rare carbon skeleton and two abietane diterpene derivatives from Salvia dorrii.

Salvidorol (1), a irregular nor-abietane-type diterpene, was isolated from the aerial parts of Salvia dorrii, in addition to two epimeric abietane diterpenes (2 and 3). This is the first report of a nor-diterpene with an irregular skeleton. The structures were established by high-field NMR techniques ((1)H-(1)H COSY, DEPT, HMQC, HMBC, NOESY and HRMS) and in case of 2 was confirmed by X-ray analysis.

Abietanes↗
PubMed2006

The membrane skeleton in Paramecium: Molecular characterization of a novel epiplasmin family and preliminary GFP expression results.

Previous attempts to identify the membrane skeleton of Paramecium cells have revealed a protein pattern that is both complex and specific. The most prominent structural elements, epiplasmic scales, are centered around ciliary units and are closely apposed to the cytoplasmic side of the inner alveolar membrane. We sought to characterize epiplasmic scale proteins (epiplasmins) at the molecular level. PCR approaches enabled the cloning and sequencing of two closely related genes by amplifications of sequences from a macronuclear genomic library. Using these two genes (EPI-1 and EPI-2), we have contributed to the annotation of the Paramecium tetraurelia macronuclear genome and identified 39 additional (paralogous) sequences. Two orthologous sequences were found in the Tetrahymena thermophila genome. Structural analysis of the 43 sequences indicates that the hallmark of this new multigenic family is a 79 aa domain flanked by two Q-, P- and V-rich stretches of sequence that are much more variable in amino-acid composition. Such features clearly distinguish members of the multigenic family from epiplasmic proteins previously sequenced in other ciliates. The expression of Green Fluorescent Protein (GFP)-tagged epiplasmin showed significant labeling of epiplasmic scales as well as oral structures. We expect that the GFP construct described herein will prove to be a useful tool for comparative subcellular localization of different putative epiplasmins in Paramecium.

Amino Acid Sequence↗
PubMed2004

Gradient enhanced selective experiments in the 1H NMR chemical shift assignment of the skeleton and side-chain resonances of stigmasterol, a phytosterol derivative.

The applicability of homonuclear gradient enhanced NMR experiments is demonstrated in the structure determination of steroid derivatives using stigmasterol as a model compound. High resolution 1H NMR spectra of steroids very often display well resolved multiplets usually in the low-field region, and these signals can be used as starting points in several selective NMR experiments to study scalar (J coupling), and dipolar (NOE) interactions. Selective excitation was carried out using a double pulsed-field gradient spin-echo sequence (DPFGSE) in which 180 degrees Gaussian pulses are sandwiched between sine shaped z-gradients. Scalar interactions were studied by homonuclear DPFGSE-COSY, DPFGSE-relay-COSY and DPFGSE-TOCSY experiments, while DPFGSE-NOESY was used to monitor spatial environment of the selectively excited proton. These methods provided unambiguous assignments for signals of the main skeleton and the side-chain of the steroid molecule. In addition, they allowed determination of the conformationally important homonuclear proton-proton coupling constants (J).

Magnetic Resonance Spectroscopy↗
PubMed2004

Skeletons, noise and population growth: the end of an old debate?

Population dynamics models remain largely deterministic, although the presence of random fluctuations in nature is well recognized. This deterministic approach is based on the implicit assumption that systems can be separated into a deterministic part that captures the essential features of the system and a random part that can be neglected. But is it possible, in general, to understand population dynamics without the explicit consideration of random fluctuations? Here, we suggest perhaps not, and argue that the dynamics of many systems are a result of interactions between the deterministic nonlinear skeleton and noise.

Journal Article↗
PubMed2006

Postnatal allometry of the skeleton in Tupaia glis (Scandentia: Tupaiidae) and Galea musteloides (Rodentia: Caviidae)--a test of the three-segment limb hypothesis.

During the evolution of therian mammals, the two-segmented, sprawled tetrapod limbs were transformed into three-segmented limbs in parasagittal zig-zag configuration (three-segment limb hypothesis). As a consequence, the functional correspondence of limb segments has changed (now: scapula to thigh, upper arm to shank, fore arm plus hand to foot). Therefore, the scapula was taken into account in the current study of the postnatal growth of the postcranial skeleton in two small mammalian species (Tupaia glis, Galea musteloides). Comparisons were made between the functionally equivalent elements and not in the traditional way between serially homologous segments. This study presents a test of the three-segment limb hypothesis which predicts a greater ontogenetic congruence in the functionally equivalent elements in fore and hind limbs than in the serially homologous elements. A growth sequence, with decreasing regression coefficients from proximal to distal, was observed in both species under study. This proximo-distal growth sequence is assumed to be ancestral in the ontogeny of eutherian mammals. Different reproductive modes have evolved within eutherian mammals. To test the influence of different life histories on ontogenetic scaling during postnatal growth, one species with altricial juveniles (Tupaia glis) assumed to be the ancestral mode of development for eutherians and one species with derived, precocial young (Galea musteloides) were selected. The growth series covered postnatal development from the first successive steps with a lifted belly to the adult locomotory pattern; thus, functionally equivalent developmental stages were compared. The higher number of allometrically positive or isometrically growing segments in the altricial mammalian species was interpreted as a remnant of the fast growth period in the nest without great locomotor demands, and the clearly negative allometry in nearly all segments in the precocial young was interpreted as a response to the demand on early locomotor activity. Different life histories seem to have a strong influence on postnatal ontogenetic scaling; the effects of the developmental differences are still observable when comparing adults of the two species.

Aging↗
PubMed2002

Skeletonization of the right gastroepiploic artery using an ultrasonic scalpel.

A new method to skeletonize and harvest the right gastroepiploic artery using an ultrasonic scalpel is presented. The technique is simple and safe, and it causes less bleeding. It is possible not only to harvest the artery faster, but to obtain large spasm-free arterial conduits for coronary artery bypass grafting.

Coronary Angiography↗
PubMed1987

The skeletonized internal mammary artery.

The internal mammary artery increasingly is being used to construct multiple distal anastomoses. By skeletonizing the pedicle, the artery is functionally lengthened and sequential anastomoses are easier to perform.

Blood Vessel Prosthesis↗
PubMed1998

A brimmed valved conduit in repair of fibrous skeleton abscess.

Aortomitral common annular involvement, which is not uncommon in infective endocarditis, necessitates deliberate surgical procedures. To repair fibrous skeleton abscess accompanied with annuloaortic ectasia, we used a brimmed valved conduit. Tension-free reconstruction of the aortic root and aortomitral common annulus was easily performed with this method.

Abscess↗
PubMed1990

The membrane skeleton of erythrocytes. A percolation model.

The spectrin network on the cytoplasmic surface of the erythrocyte membrane is modeled as a triangular lattice of spectrin tetramers. This network obstructs lateral diffusion of proteins and provides mechanical reinforcement to the membrane. These effects are treated in a systematic and unified manner in terms of a percolation model. The diffusion coefficient is obtained as a function of the fraction of normal spectrin tetramers for both static and fluctuating barriers. The elasticity of the network is calculated as a function of the fraction of normal spectrin and the ratio of bending to stretching energies. For static barriers, elasticity and lateral diffusion are incompatible: if a network is connected enough to be elastic, it is connected enough to block long-range lateral diffusion. The elasticity and the force required for mechanical breakdown go to zero at the percolation threshold; experimental evidence suggests the existence of a stability threshold at or near the percolation threshold. The model is qualitatively applicable to other cells with membrane skeletons, such as epithelial cells, in which localization of membrane proteins is essential to differentiation.

Algorithms↗
PubMed1991

Membrane fluctuations in erythrocytes are linked to MgATP-dependent dynamic assembly of the membrane skeleton.

The observation of low-frequency fluctuations of the cell membrane in erythrocytes and in several nucleated cells suggests that this phenomenon may be a general property of the living cell. A study of these fluctuations in human erythrocytes and its ghosts has now been carried out using a novel optical method based on point dark field microscopy. We have demonstrated that the reestablishment of membrane fluctuations in erythrocyte ghosts is dependent on MgATP but does not necessarily require the restoration of the biconcave shape. The results imply that the dominant component of membrane fluctuations are metabolically dependent and suggest the existence of a dynamic mechano-chemical coupling within the membrane skeleton network induced by MgATP.

Adenosine Triphosphate↗
PubMed1992

Spin-labeling studies of the conformation of the Ca(2+)-regulatory protein calmodulin in solution and bound to the membrane skeleton in erythrocyte ghosts: implications to transmembrane signaling.

Electron paramagnetic resonance (EPR) studies of the Ca(2+)-regulatory protein calmodulin (CaM) have been performed. The conformation of CaM in solution changes upon binding of Ca2+ allowing the protein to bind to target proteins existing in the red blood cell membrane. In this study a maleimide spin label, covalently attached to the single cysteine residue of CaM located in the first Ca(2+)-binding domain, was used to monitor allosteric conformational changes induced by interaction of CaM with Ca2+ and subsequently with the red blood cell membrane. The results show, relative to apo-CaM, a significant increase in the apparent rotational correlation time, tau, of the spin label when Ca2+ was present in solution (P less than 0.001). When apo-CaM exposed to red blood cell membrane ghosts in the absence of Ca2+, no significant difference in spin label motion was seen relative to solution, consistent with the idea that Ca2+ is required for CaM to bind to skeletal proteins. When Ca2+ was added to CaM which was then exposed to ghosts, a highly significant increase in tau (decrease in motion) (P less than 0.000001) relative to apo-CaM exposed to ghosts was found. This latter increase in tau is significantly greater than that produced by the addition of Ca2+ to CaM in solution (P less than 0.001). The major interaction sites of CaM were found by photoaffinity labeling and autoradiography on SDS-PAGE to be on the principal skeletal protein, spectrin. EPR was also used to investigate the biophysical correlates of transmembrane signaling. Spin-labeled CaM was bound to the membrane skeleton in the presence of Ca2+. On the opposite side of the erythrocyte membrane a lectin was bound to the external glycoconjugate of Band 3, the major transmembrane protein of the erythrocyte. A highly significant increase in T of the maleimide spin probe was found relative to the control system in which the lectin was absent. (P < 0.00001). These results suggest that electron paramagnetic resonance spectra of spin-labeled CaM can provide useful information about protein structure and function when in solution and when bound to membranes.

Autoradiography↗