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At least 1,495 records · Page 83Linked to original sources
PubMed2000

Mouse Gli1 mutants are viable but have defects in SHH signaling in combination with a Gli2 mutation.

The secreted factor Sonic hedgehog (SHH) is both required for and sufficient to induce multiple developmental processes, including ventralization of the CNS, branching morphogenesis of the lungs and anteroposterior patterning of the limbs. Based on analogy to the Drosophila Hh pathway, the multiple GLI transcription factors in vertebrates are likely to both transduce SHH signaling and repress Shh transcription. In order to discriminate between overlapping versus unique requirements for the three Gli genes in mice, we have produced a Gli1 mutant and analyzed the phenotypes of Gli1/Gli2 and Gli1/3 double mutants. Gli3(xt) mutants have polydactyly and dorsal CNS defects associated with ectopic Shh expression, indicating GLI3 plays a role in repressing Shh. In contrast, Gli2 mutants have five digits, but lack a floorplate, indicating that it is required to transduce SHH signaling in some tissues. Remarkably, mice homozygous for a Gli1(zfd )mutation that deletes the exons encoding the DNA-binding domain are viable and appear normal. Transgenic mice expressing a GLI1 protein lacking the zinc fingers can not induce SHH targets in the dorsal brain, indicating that the Gli1(zfd )allele contains a hypomorphic or null mutation. Interestingly, Gli1(zfd/zfd);Gli2(zfd/+), but not Gli1(zfd/zfd);Gli3(zfd/+) double mutants have a severe phenotype; most Gli1(zfd/zfd);Gli2(zfd/+) mice die soon after birth and all have multiple defects including a variable loss of ventral spinal cord cells and smaller lungs that are similar to, but less extreme than, Gli2(zfd/zfd) mutants. Gli1/Gli2 double homozygous mutants have more extreme CNS and lung defects than Gli1(zfd/zfd);Gli2(zfd/+) mutants, however, in contrast to Shh mutants, ventrolateral neurons develop in the CNS and the limbs have 5 digits with an extra postaxial nubbin. These studies demonstrate that the zinc-finger DNA-binding domain of GLI1 protein is not required for SHH signaling in mouse. Furthermore, Gli1 and Gli2, but not Gli1 and Gli3, have extensive overlapping functions that are likely downstream of SHH signaling.

Abnormalities, Multiple↗
PubMed2003

Surgical removal of a dislocated lower third molar from the condyle region: case report.

INTRODUCTION: Migration of dislocated lower third molar into the condylar region is quite rare. Attention should be taken to avoid condyle fracture. METHODS: 49-year-old patient had an ectopic lower left third molal in the condylar region, suffered from a submandibular and masseter space abscess. Removal of the molar via intraoral approach was chosen avoiding facial nerve branches and unnecessary scar formation. Coronoid process is removed, the tooth is separated and removed. The defect is filled with iliac cancellous bone. The coronoid process was fixed as a cover with a resorbable plate and screws (BIONX). RESULTS: Removal via intraoral approach is possible. Hypesthesia existed postoperatively, became normal later. CONCLUSION: Annual observation is strongly recommended. Intraoral approach is superior to the extraoral approach. Removal of the coronoid process minimizes the masticator forces. Separation of the tooth is essential. Filling the defect with cancellous bone accelerates the healing.

Abscess↗
PubMed2003

Parasites of South African wildlife. XVII. Ostertagia triquetra n. sp. (Nematoda: Trichostrongylina) from the grey rhebuck, Pelea capreolus (Forster, 1790).

Re-examination of Teladorsagia hamata (Mönnig, 1932) Durette-Desset, 1989 reported from grey rhebuck, Pelea capreolus (Forster, 1790) proved it to be a new species of Ostertagi Ransom, 1907. The new species, for which the name Ostertagia triquetra n. sp. is proposed, differs from Teladorsagia hamata in the configuration of the bursal rays (2-1-2 in the former, 2-2-1 in the latter), and in that the interno-dorsal branch of the spicules bears a process that is triangular and convex in the new species, but concave and shaped like an ice-cream scoop in Teladorsagia hamata. Ostertagia triquetra has so far been found only in grey rhebuck in the Eastern Cape Province while Teladorsagia hamata was recorded from springbok, Antidorcas marsupialis (Zimmerman, 1780) and gemsbok, Oryx gazella (Unnaeus, 1758) in the western part of the country.

Animals↗
PubMed2004

[Preliminary analysis on the proteomic feature of Guillain-Barré syndrome-associated Campylobacter jejuni].

OBJECTIVE: To search the marker proteins of Guillain-Barré syndrome (GBS)-associated Campylobacter jejuni (C. jejuni) by comparing the protein maps of GBS-associated C. jejuni strains with that of non-GBS-associated C. jejuni strains. METHODS: The whole-cell proteins of eight GBS-associated and eight non-GBS-associated C. jejuni strains were separated using the two-dimensional gel electrophoresis respectively. The differentially expressed proteins between the two sets of strains were identified by matrix-assisted laser desorption/ionization-time of flight mass spectrometry (MALDI-TOF-MS) after in-gel tryptic digestion. RESULTS: Twenty differentially expressed spots were found with seventeen identified ones using MSCOT database. These proteins were identified as wlaX protein and some other proteins involving in energy metabolism (malate dehydrogenase, triosephosphate isomerase, Ni/Fe-hydrogenase small chain, cysteine synthase, branched-chain amino acid aminotransferase), cell process (heat shock protein, iron-uptake ABC transport system periplasmic iron-binding protein, alkyl hydroperoxide reductase), cell envelope (flagellin, UDP-N-acetylenolpyruvoylglucosamine reductase) etc. CONCLUSION: WlaX proteins were probably associated with LPS biosynthesis or virulence of C. jejuni. WlaX protein and flagellin protein were the possible marker-proteins of GBS-associated C. jejuni strains.

Campylobacter jejuni↗
PubMed2004

The incidence of a superficial arterial pattern in the human upper extremities.

The incidence of superficial arteries was studied in 68 (38 right and 30 left) upper extremities. One right limb of an adult male presented a superficial arterial pattern (2.63%, total 1.47%) resembling a superficial brachio-ulno-radial artery (SBUR). The median nerve crossed the superficial brachial artery (SBA) from the posterior to the medial side and again posterior to the same at the cubital fossa. The superficial brachial artery divided into superficial radial and superficial ulnar arteries, which coursed distally superficial to the muscles but deep to the deep fascia. The superficial radial artery passed deep to the extensor tendons of the thumb. The superficial ulnar artery gave only muscular branches in the forearm. The superficial radial artery gave origin to the radial recurrent artery and the common interosseous trunk. The latter gave origin to a palmar type of median artery, muscular branches, and an artery that divided into anterior and posterior ulnar recurrent arteries. It also gave origin to the anterior and posterior interosseous arteries. The latter provided the interosseous recurrent artery and a branch that coursed towards the olecranon process of the ulna. The knowledge of this variation is important since it may be compromised in surgical procedures of the upper limb.

Adult↗
PubMed1991

[Clinico-electrophysiological changes in the neuromuscular system of patients with vibration disease].

Neuromuscular alterations associated with vibratory disease related to the pathology of spinal motoneurons, axon (degeneration, demyelinization), synapse, muscle. The site, nature and the intensity of the process depended on the duration of work with vibroinstruments, industrial characteristics. During specialized employment, the patients manifested aggravation of the clinical and neurophysiological parameters of the denervation process. Compensatory innervation of the muscles (branching of axon terminals, establishment of new neuromuscular contacts, ets.) was most effective in polishers and riveters. Foundry cleaners demonstrated a tendency toward progress of neuromuscular pathology. To explain motor disorders in patients with vibratory disease, the mechanisms of microtraumatization of nerve endings followed by involvement of the neurotrophic and neuroreflectory systems are suggested.

Action Potentials↗
PubMed1988

Synthesis and biologic evaluation of 1-[11C]-3,3-dimethylheptadecanoic acid.

1-[11C]-3,3-dimethylheptadecanoic acid [( 11C]DMHDA) has been prepared for evaluation as a potential myocardial metabolism indicator based on an expected intrinsic stability toward beta-oxidative metabolic processes. Synthesis of this novel branched-chain fatty acid was accomplished by copper-catalyzed addition of tetradecylmagnesium bromide to diethylisopropylidenemalonate. Subsequent saponification and decarboxylation afforded 3,3-dimethylheptadecanoic acid (DMHDA) that was converted to the corresponding alkyl bromide by means of a modified Hunsdiecker reaction. Carboxylation of 2,2-dimethylhexadecylmagnesium bromide with 11CO2 gave [11C]DMHDA. Carbon-11 DMHDA showed moderate myocardial uptake in fasted rats, albeit lower than that reported for the 3-monomethyl analog. Considerable washout of radioactivity from the heart was also observed over the first 30 min postinjection. Imaging in dogs likewise showed disappointing heart uptake with much higher localization in the lung. These data suggest that gem-dimethyl substitution of the beta-position in long chain fatty acids is not only insufficient for enhanced myocardial uptake and retention, but also, may be deleterious when compared with beta-monomethylation.

Animals↗
PubMed1984

[Integration of psychotherapy into clinical medicine in Germany--contribution of J. H. Schultz].

Based on a short description of the situation of the psychotherapy in Germany during the 20ties Schultz's achievements in this period are defined and compared. In the first instance Schultz played a leading role in the integration-process of psychotherapy in several clinical branches. Furthermore Schultz tried to develop a medico-psychological concept for practical medicine in general which possesses a high importance in the present discussion about medico-psychological problems.

Germany↗
PubMedDate not supplied

[Formation of mitochondrial reticulum in the diaphragmatic muscle in rat ontogeny].

The development of a complex system of mitochondrial reticulum of the rat diaphragm muscle fibers proceeds in several steps during ontogenesis. At first (19 day-old embryo and early postnatal period) the mitochondria grow in the longitudinal (with respect to the muscle fiber) direction, being located in the intermyofibrillar spaces. On the 9-10th day after birth there appear mitochondrial processes perpendicular to the long axis of muscle fiber at the levels of isotropic myofibrillar discs. These processes are later replaced by the branched giant mitochondria lying as if in floors across the muscle fiber. All mitochondria are interconnected by means of special contacts in a single system of mitochondrial reticulum. The functional role of complex mitochondria in the cross-striated muscle is discussed.

Animals↗
PubMed1996

Spatially restricted increase in polysialic acid enhances corticospinal axon branching related to target recognition and innervation.

The polysialic acid (PSA) modification of the neural cell adhesion molecule (NCAM) has been shown to alter the responses of developing axons to their environment. We have studied the potential role of PSA in regulating the innervation of the spinal cord by corticospinal axons, which occurs by a delayed formation of collateral branches from the parent axons. Developmental changes in the distribution of PSA were examined immuno-histochemically using light and electron microscopy. Whereas NCAM is distributed along the entire pathway of rat corticospinal axons as they grow from the cortex to the spinal cord, PSA-modified NCAM does not become evident until later. When PSA becomes evident, it is restricted to the distal segment of these axons from the caudal hindbrain through the spinal cord. The increase in PSA on corticospinal axons coincides with the time that they begin to form collateral branches in the spinal cord. This unique spatiotemporal distribution of PSA suggests its involvement in corticospinal axon branching. To test this hypothesis, PSA was selectively removed by an in vivo injection of endoneuraminidase N. This treatment did not seem to interfere with the pathfinding of corticospinal axons; however, PSA removal delayed the onset of collateral branching by corticospinal axons within the spinal cord and later diminished the magnitude of branching. These findings indicate a role for PSA in the regulation of interstitial axon branching, a crucial step in the process of target recognition and innervation by corticospinal axons.

Animals↗
PubMed1999

Branched oligonucleotide-intercalator conjugate forming a parallel stranded structure inhibits HIV-1 integrase.

Integration of a DNA copy of the HIV-1 genome into chromosomal DNA of infected cells is a key step of viral replication. Integration is carried out by integrase, a viral protein which binds to both ends of viral DNA and catalyses reactions of the 3'-end processing and strand transfer. A 3'-3' branched oligonucleotide functionalised by the intercalator oxazolopyridocarbazole at each 5'-end was found to inhibit integration in vitro. We show that both a specific (G,A) sequence and the OPC intercalating agent contribute to the capability of the branched oligonucleotide to form a parallel stranded structure responsible for the inhibition.

Base Sequence↗
PubMed2006

Clean prediction of CP-violating processes psi, phi, and Gamma decay to KSKS and KLKL.

The ratio of K(S)K(S) (K(L)K(L)) and K(L)K(L) production rates is calculated by considering K(0) - K(0) oscillation in J/psi --> K(0)K(0) decay. The theoretical uncertainty due to strong interaction in J/psi decay is completely canceled in the ratio; therefore, the absolute branching fractions of the CP-violating processes of J/psi --> K(S)K(S) and K(L)K(L) can be cleanly and model-independently determined in the case that J/psi K(S)K(L) decay is precisely measured. In the future tau-charm factory, the expected CP violating process of J/psi --> K(S)K(S) should be reached. It is important to measure J/psi to K(S)K(S) and K(S)K(L) decays simultaneously, so that many systematic errors will be canceled. More precise measurements are suggested to examine the predicted isospin relation in J/psi --> KK decays. All results can be extended to decays of other vector quarkonia, phi, psi(2S), and gamma(1S), etc.

Journal Article↗
PubMed1997

Formation of the branching pattern of blood vessels in the wall of the avian yolk sac studied by a computer simulation.

The present study was performed to provide data to support the notion previously believed but not proved experimentally or theoretically, that blood vessels are formed by the selection of capillaries in the network. In an attempt to understand the mechanism of formation of blood vessel branching structures, the transformation of a capillary network to a branching system in the wall of quail yolk sac was successively recorded by a series of photographs, and a computer simulation was carried out for the process of in vivo vascularization based on the photographs. The simulation demonstrated that a positive feedback system participated in the formation of a branching structure. That is, vessels which had been much used were enlarged, whereas less used vessels were reduced in their size and finally extinguished. The enlarged vessels became major components of the branching system. As the body of an embryo grew, it was observed that polygonal capillary networks enlarged, which led each polygon of the network to divide into a few finer polygons. Then, some of the capillary vessels were again selected and formed a branching system. This process repeated during the body growth, indicating that the vascular system developed adaptively to the body growth. A region where the growth was fast, received much blood flow and produced finer networks of capillaries. Thus, it was experimentally demonstrated for the first time that capillaries in the network are successively selected by a positive feedback mechanism and form blood vessels.

Animals↗
PubMed2000

Stochastic model of hysteresis

The methods of the probability theory have been used in order to build up a model of hysteresis which is different from the well-known Preisach model. It is assumed that the system consists of large number of abstract particles in which the variation of an external control parameter (e.g., the magnetic field) may result in transitions between two states S((+)) and S((-)). The state of a particle is characterized by the value +1 or -1 of a random variable (e.g., the magnetization direction parallel or antiparallel to the magnetic field). The transitions are governed by two further random variables corresponding to the S((-))-->S((+)) and the S((+))-->S((-)) transitions (e.g., "up switching" and "down switching magnetic field"). The method presented here makes it possible to calculate the probability distribution and consequently the expectation value of the number of particles in the S((+)) (or S((-))) state for both increasing and decreasing parameter values, i. e., the hysteresis curves of the transitions can be determined. It turns out that the reversal points of the control parameter are Markov points which determine the stochastic evolution of the process. It has been shown that the branches of the hysteresis loop are converging to fixed limit curves when the number of cyclic back-and-forth variations of the control parameter between two consecutive reversal points is large enough. This convergence to limit curves gives a clear explanation of the accommodation process. The accommodated minor loops show the return-point memory property but this property is obviously absent in the case of nonaccommodated minor loops which are not congruent and generally not closed. In contrast to the traditional Preisach model the reversal point susceptibilities are nonzero finite values. The stochastic model can provide a surprisingly good approximation of the Raylaigh quadratic law when the external parameter varies between two sufficiently small values. The practical benefits of the model can be seen in the numerical analysis of the derived equations. On one hand the calculated curves are in good qualitative agreement with the experimental observations and on the other hand, the estimation of the joint distribution function of the up and down switching fields can be performed by using the measured hysteresis curves.

Journal Article↗
PubMed2003

Strange attractors are classified by bounding Tori.

There is at present a doubly discrete classification for strange attractors of low dimension, d(L)<3. A branched manifold describes the stretching and squeezing processes that generate the strange attractor, and a basis set of orbits describes the complete set of unstable periodic orbits in the attractor. To this we add a third discrete classification level. Strange attractors are organized by the boundary of an open set surrounding their branched manifold. The boundary is a torus with g holes that is dressed by a surface flow with 2(g-1) singular points. All known strange attractors in R3 are classified by genus, g, and flow type.

Journal Article↗
PubMed1994

[The histopathology of the trabecular section of the right branch of the bundle of His in chronic chagasic patients with a right bundle-branch block].

PURPOSE: To evaluate possible morphological changes in chronic chagasic of the right bundle trabecular branch (RB) with right branch block (RBB) and to draw clinicopathological correlations. METHODS: Eight RBB chronic chagasic septo-marginal trabeculae (SMT) (group A), six left branch block (LBB) chagasic SMT (group B) and six SMT from non-chagasics with no heart disease (group C) were analyzed. Every SMT was completely embedded in paraffin, sub-serially sectioned to the end of the paraffin-block and the sections were processed for pathological study. RESULTS: Right bundle branch trabecular segment mononuclear infiltrate and/or fibrosis were found for 87.5 (7/8) of group A, 50% (3/6) of group B and 16.6% (1/6) of group C. Moderate mononuclear infiltrate and fibrosis were noted respectively for 3 and 1 cases, from group A. For the remaining group A cases and for all the group B and C cases the mononuclear infiltrate and fibrosis were slight. CONCLUSION: The frequency and degree of RB lesions might explain some of RBB. On the other hand, the absence of lesions in one case RBB and the slight degree of RB lesions in chagasics with LBB and in one non-chagasic case indicate that sometimes it is not possible to establish electrocardiographic-pathological correlations after TSM histological examination.

Adult↗
PubMed1995

Dependence of frequency of homologous recombination on the homology length.

The frequency of homologous recombination is believed to be a linear function of the length (N bp) of homology between DNAs. Here, the N intercept is believed to be determined by a threshold length below which some physical constraint is effective. In the mammalian gene targeting systems, however, the frequency depends more steeply than linearly on the homology length. To explain both the linear dependence and the steeper dependence, we propose a model where the branch point of a reaction intermediate is assumed to "walk randomly" along the homologous region until it is processed. The intermediate is assumed to be destroyed if the branch point ever reaches either end of the homology. In this model, the length dependence is governed by a parameter, h, which is defined as efficiency of processing of the intermediate and reflects unlikelihood of the destruction at either end of the homology. We find that the frequency is proportional to N3 for smaller N and is a linear function of N for larger N. Where the shift from the N3 dependence to the linear dependence takes place is determined by the parameter h. The range of N showing the N3 dependence becomes narrower as h becomes larger. The dependence steeper than linear dependence, which is observed not only in the mammalian gene targeting system but also in bacteriophage T4, Escherichia coli and yeast systems, agrees well with the predicted N3 dependence. The N intercept is determined not by physical (or structural) constraints but only by the parameter h in this model.

Animals↗