Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UNIPROT:P50583 (asymmetrical)
 12,197 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A mild and general route for preparing pyridines from nitriles and diynes is described. Ni/imidazolyidene complexes were used to mediate cyclization alkynes and both aryl and alkyl nitriles at ambient temperature. In addition, the efficacy of this protocol allows for the preparation of a fused seven-membered pyridone and for intermolecular cyclizations. When an asymmetrical diyne was employed, cyclization afforded a single pyridine regioisomer.
 ...
PMID:A nickel-catalyzed route to pyridines. 1581 Aug 32

Examination of the spiral intestines of 44 freshwater stingrays, Potamotrygon motoro, from tributary rivers of the Parana River in Argentina, allowed for the collection of specimens of an undescribed species of Acanthobothrium. Acanthobothrium ramiroi n. sp. can be distinguished from all other congeners by the combination of the following characters: asymmetrical hooks (medial and lateral hooks conspicuously different in size and form, with axial prong of medial hooks stouter than abaxial prong), hook size (total length of medial hooks up to 242 microm, total length of lateral hooks up to 239 microm), bothridia not fused to the scolex proper at posterior ends, worm size (51-84 mm long), and the presence of a conspicuous vaginal sphincter. The new species is different from all other species of Acanthobothrium in freshwater potamotrygonids, except Acanthobothrium terezae, in having conspicuous asymmetrical hooks. The main differences that allow for the distinction between A. ramiroi and A. terezae include hook size, the way the bothridia are attached to the scolex proper, and the shape of the older gravid segments. The discovery of a new species of Acanthobothrium from a potamotrygonid extends our understanding of the diversity of the genus in freshwater stingrays in South America.
 ...
PMID:A new species of Acanthobothrium (Cestoda: Tetraphyllidea: Onchobothriidae) from the ocellate river stingray, Potamotrygon motoro (Chondrichthyes: Potamotrygonidae), in Argentina. 1598 38

While spatial asymmetries have been extensively investigated in the visual modality and to a lesser degree in the tactile modality, there are no reports on auditory spatial asymmetries in neurologically normal subjects. The subjects in this study performed an auditory midline task in which they had to adjust the level of two sounds that were presented simultaneously in different hemispaces so as to make the perceived fused sound appear to emanate from the midsagittal plane. The results showed that subjects reported a sound to be central when it was lateralized to the left (i.e., more intense at the left ear), as if there were a rightward shift in the perceived location. This rightward shift was more pronounced in left-handed than in right-handed subjects, even though all the subjects had to use both hands to adjust the sound level. Gaze direction significantly modulated the shift of the perceived auditory midline: the rightward shift was maximal when the subjects' gaze direction was central and 30 degrees to the right, while it disappeared when the gaze was directed 30 degrees to the left side. These results are compared with data obtained from neglect patients in previous studies and are discussed in terms of the interaction between asymmetrical hemispheric activations in auditory spatial tasks and an asymmetrical allocation of attention between the left and right hemispaces.
 ...
PMID:Rightward shift of the auditory subjective straight ahead in right- and left-handed subjects. 1687 40

The authors conducted a study to identify radiological patterns of Klippel-Feil syndrome (KFS), and they present a new interpretation of the origin of these patterns based on recent advances in understanding of embryonic development of the spine and its molecular genetic control. The authors studied radiographs and computerized tomography (CT) scans as well as magnetic resonance images or CT myelograms obtained in 30 patients with KFS who were referred for treatment between 1982 and 1996; the patients had complained of various neuroorthopedic complications. Homeotic transformation due to mutations or disturbed expression of Hox genes is a possible mechanism responsible for C-1 assimilation, which was found to have occurred in 19 cases (63%). Notochordal defects and/or signaling problems, which result in reduced or impaired Pax-1 gene expression, may underlie vertebral fusions. This, together with asymmetrical distribution of paraxial mesoderm cells and a possible lack of communication across the embryonic midline, could cause asymmetrical fusion patterns, which were present in 17 cases (57%). The wide and flattened shape of the fused vertebral bodies and their resemblance to the embryonic cartilaginous vertebrae as well as the process of progressive bone fusion with age suggest that the fusions occur before or, at the latest, during chondrification of vertebrae. The authors suggest that the aforementioned mechanisms are likely to be, at least in part, responsible for the observed patterns in KFS that affect the craniovertebral junction and the cervical spine.
 ...
PMID:The dysmorphic cervical spine in Klippel-Feil syndrome: interpretations from developmental biology. 1697 46

Because the eyes of insects cannot be moved independently of the head, information about head posture is essential for stabilizing the visual world or providing information about the direction of gaze. We examined the external anatomy and physiological capabilities of a head posture proprioceptor, the prosternal organ (PO), located at the base of the neck in the black soldier fly, Hermetia illucens (L.) (Family: Stratiomyidae). The PO is sexually isomorphic and is composed of two fused plates of about 130 mechanosensory hairs set in asymmetrical sockets whose orientation varies across the organ. A multi-joint mechanical coupling between the head, neck membrane, and contact sclerites deflects the hairs more or less to increase or decrease their level of excitation. The PO sensory afferents project to the central nervous system (CNS) via a pair of bilateral prosternal nerves (PN) to the fused thoracic ganglia. Simultaneous recording of spiking activity in the PN and videotaping of wind-induced and voluntary head movements around all three axes of head rotation reveal that a few PN afferents are active at rest, but activity increases tonically in response to head deflections. Activity is significantly modulated by change in head angles around the pitch (+/-40 degrees ), yaw (+/-30 degrees ) and roll (more than +/-90 degrees ) axes, although the dynamic range of spiking activity differs for each axis of rotation. Prosternal nerve afferents are bilaterally excited (inhibited) by pitch down (up); excited (inhibited) by head yaw toward the ipsilateral (contralateral) side; excited by roll down toward the ipsilateral side, but little inhibited by roll toward the opposite side. Although bilateral comparison of activity in PN afferents reliably encodes head posture around a given rotational axis, from the point of view of the CNS, the problem of encoding head posture is ill-posed with three axes of rotation and only two streams of afferent information. Furthermore, when the head is rotated around more than one axis simultaneously, mechanical interactions in the neck modify the responses to postural changes around the three rotational axes, which adds further ambiguity to reliable encoding of head posture. The properties of the PO in this relatively basal fly species are compared to those of higher flies and possible mechanisms of disambiguation are discussed.
 ...
PMID:Proprioceptive encoding of head position in the black soldier fly, Hermetia illucens (L.) (Stratiomyidae). 1698 7

The purpose of this study was to investigate three-dimensional (3-D) morphology of C-shaped root canal system using micro-computed tomography (microCT) and 3-D reconstruction. There were 102 extracted mandibular second molars with fused roots collected from a native Chinese population. The teeth were scanned by microCT and reconstructed by 3-D software. The 98 teeth that possessed a C-shaped canal system were further analyzed. The 3-D reconstructed images of canals were classified into three categories: merging type (type I), symmetrical type (type II), and asymmetrical type (type III). The cross-sectional images of each tooth were submitted to computer analysis, and the minimum canal wall thickness was measured. In these 98 molars, 32 (32.65%) teeth showed a merging type appearance, 38 (38.78%) a symmetrical type and 28 (28.57%) an asymmetrical type. The minimum canal wall thickness in type I was thicker than that in type II or type III in the apical and middle portion (p < 0.05). Being fully aware of the configuration of C-shaped root canal system and the location of minimum wall thickness will ensure more efficient root canal treatment.
 ...
PMID:C-shaped canal system in mandibular second molars part IV: 3-D morphological analysis and transverse measurement. 1705 7

The purpose of this study was to investigate radiographic features of the C-shaped canal system in mandibular second molars and their relationship to the canal anatomy by using intraradicular contrast medium and micro-computed tomography (microCT) scanning. Thirty mandibular second molars with fused roots were collected and stored in 10% formalin solution. After being scanned by microCT and reconstructed with 3-dimensional software, the pulp tissue of each tooth was removed mechanically and chemically. The contrast medium was introduced into the canal by using a specialized device, and the buccal-lingual radiograph was taken for each tooth. The radiographic images were classified into 3 types: Types I (merging type), II (symmetrical type), and III (asymmetrical type). The relationship between the radiographic and anatomic features was analyzed by collating the microCT scanned canal images with the radiographic types. The results were subject to Kruskal-Wallis test. Findings showed that 10 teeth were Type I, 10 teeth Type II, and 10 teeth Type III. Types I and III had more C1, C2 canal shape in their canal orifice, coronal, and middle canal portion than the Type II (P < .05). Types II and III had more C3a, C3b canal shapes in the apical canal portion than Type I (P < .05). On the basis of these results, the radiographic features revealed by the intraradicular contrast medium can help to identify the canal anatomy of C-shaped canal system in mandibular second molars.
 ...
PMID:Identification of C-shaped canal in mandibular second molars. Part I: radiographic and anatomical features revealed by intraradicular contrast medium. 1780 16

Density functional theory (DFT) calculations were carried out to study the inner hydrogen atom transfer in low symmetrical metal-free tetrapyrrole analogues ranging from tetraazaporphyrin H(2)TAP (A(0)B(0)C(0)D(0)) to naphthalocyanine H(2)Nc (A(2)B(2)C(2)D(2)) via phthalocyanine H(2)Pc (A(1)B(1)C(1)D(1)). All the transition paths of sixteen different compounds (A(0)B(0)C(0)D(0)-A(2)B(2)C(2)D(2) and A(0)B(0)C(m)D(n), m <or= n <or= 3) are fully optimized at the B3LYP/6-31G(d) level and vibration analyses have been conducted to verify the optimized structures. It is revealed that the number and position of fused benzene rings onto the TAP skeleton have significant effect on the potential energy barrier of the inner hydrogen atom transfer. Introducing fused benzene rings onto the hydrogen-releasing pyrrole rings can increase the transitivity of inner hydrogen atom and thus lower the transfer barrier of this inner hydrogen atom while fusing benzene rings onto the hydrogen-accepting pyrrole rings will increase the hydrogen transfer barrier to this pyrrole ring. The transient cis-isomer intermediate with hydrogen atoms joined to the two adjacent pyrrole rings with less fused benzene rings is much stable than the others. It is also found that the benzene rings fused directly onto pyrrole rings have more effect on the inner hydrogen atom transfer than the outer benzene rings fused onto the periphery of isoindole rings. The present work, representing the first effort towards systematically understanding the effect of ring enlargement through asymmetrical peripheral fusion of benzene ring(s) onto the TAP skeleton on the inner hydrogen transfer of tetrapyrrole derivatives, will be helpful in clarifying the N-H tautomerization phenomenon and detecting the cis-porphyrin isomer in bio-systems.
 ...
PMID:Inner hydrogen atom transfer in benzo-fused low symmetrical metal-free tetraazaporphyrin and phthalocyanine analogues: density functional theory studies. 1909 16

Early Cambrian tommotiids are problematic fossil metazoans with external organophosphatic sclerites that have been considered to be basal members of the lophophorate stem group. Tommotiids are almost exclusively known from isolated or rarely fused individual sclerites, which made previous reconstructions of the actual organism highly conjectural. However, the recent discovery of the first articulated specimens of the tommotiid Eccentrotheca revealed a tubular sclerite arrangement (scleritome) that limited the possible life habit to sessile filter feeding and thus further supported a lophophorate affinity. Here, we report the first articulated specimens of a second tommotiid taxon, Paterimitra from the Early Cambrian of the Arrowie Basin, South Australia. Articulated specimens of Paterimitra are composed of two bilaterally symmetrical sclerite types and an unresolved number of small, asymmetrical and irregular crescent-shaped sclerites that attached to the anterior margin of the symmetrical sclerites. Together, the sclerites form an open cone in which the symmetrical sclerites are joined together and form a small posterior opening near the base of the scleritome, while the irregular crescent-shaped sclerites defined a broad anterior opening. The coniform scleritome of Paterimitra is interpreted to have attached to hard substrates via a pedicle that emerged through the small posterior opening (sometimes forming a tube) and was probably a sessile filter feeder. The scleritome of Paterimitra can be derived from the tubular scleritome of Eccentrotheca by modification of basal sclerites and reduction in tube height, and probably represents a more derived member of the brachiopod stem group with the paired symmetrical sclerites possibly homologous to brachiopod valves.
 ...
PMID:The scleritome of Paterimitra: an Early Cambrian stem group brachiopod from South Australia. 1920 19

Inhomogeneous surrounds can produce either asymmetrical or symmetrical increment/decrement induction by orienting T-junctions to selectively group a test patch with surrounding regions [Melfi, T., & Schirillo, J. (2000). T-junctions in inhomogeneous surrounds. Vision Research, 40, 3735-3741]. The current experiments aimed to determine where T-junctions are processed by presenting each eye with a different image so that T-junctions exist only in the fused percept. Only minor differences were found between retinal and cortical versus cortical-only conditions, indicating that T-junctions are processed cortically.
 ...
PMID:The anatomical locus of T-junction processing. 1946 13


<< Previous 1 2 3 4 5 6 7 Next >>