2,535 research outputs found
Late Mesozoic-Cenozoic exhumation history of the Lesser Hinggan Mountains, NE China, revealed by fission track thermochronology
No full textTunable visual color filter using microfluidic grating
No full textAuthor name used in this publication: X. M. Zhang2010-2011 > Academic research: refereed > Publication in refereed journalVersion of RecordPublishedVoR allowe
Dendrolycopodium verticale comb. nov (Lycopodiopsida: Lycopodiaceae) from China
No full textA new combination in the lycophyte genus Dendrolycopodium (Lycopodiacae) from Lycopodium, D. verticale (Li Bing Zhang) Li Bing Zhang & X. M. Zhou, for a Chinese species is made
Diverse exhumation of the Mesozoic tectonic belt within the Yangtze Plate, China, determined by apatite fission-track thermochronology
No full textRisk factors associated with unsatisfactory hip function in children with late-diagnosed developmental dislocation of the hip treated by open reduction
No full texta b s t r a c t
Background: Open reduction with or without pelvic and femoral osteotomy is the accepted treatment
option for children older than 18 months with developmental dislocation of the hip (DDH). However, few
studies have investigated hip function in children with late DDH treated by open reduction. Therefore, we
performed a retrospective study investigating the risk factors potentially associated with unsatisfactory
hip function.
Hypothesis: We hypothesized that some risk factors can be associated with unsatisfactory hip function
in patients with late DDH treated by open reduction.
Patients and methods: We retrospectively reviewed the clinical and radiographic data of 79 children (98
hips, mean age 39.7 ± 18.6 months; range, 19–95.3) with late-detected DDH treated by open reduction.
Acetabular index (AI), Tönnis grade, Center Edge Angle (CEA), avascular necrosis of the femoral epiphysis
(AVN), and Severin radiographic grade were evaluated on radiographs. Hip function was rated according
to modified Outcome Evaluation Standard for Congenital Dislocation of the Hip with a maximum score of
15. According to type of surgery, patients were divided into four groups: open reduction alone (Group A),
open reduction in conjunction with pelvic osteotomy (Group B), and open reduction in conjunction with
femoral osteotomy and Pemberton/Salter (Group C) or Bernese-type triple pelvic osteotomy (Group D).
Analysis of variance (ANOVA), t-test, chi-square test, and multivariate regression analysis were used to
evaluate the independent risk factors of unsatisfactory hip function.
Results: The mean hip function score was 10.8 ± 2.8 (4.5–15); 61 hips (62.2%) had satisfactory function
(23 [23.5%] excellent and 38 [38.8%] good), while 37 hips (37.8%) had unsatisfactory function (16 [16.3%]
fair and 21 [21.4%] poor). Spearman correlation analysis indicated that age at surgery was negatively
correlated with function score (r = −0.326, p = 0.001). The age of patients with satisfactory hip function
(34.5 ± 14.2 months; range, 19.4−74.8) was significantly lower than those with unsatisfactory function
(43.7 ± 21 months; range, 20.6–95.3) (p = 0.011). The hip function score in Group A (14.2 ± 0.8; range,
12.8–15) was significantly higher than in the other three groups (p < 0.001). Hip function score in patients
with type III or IV AVN was significantly lower than those without AVN, or with type II AVN (p = 0.001).
Multivariate regression analysis confirmed age at surgery, type of surgery and AVN were negatively
correlated with hip function score. Logistic regression analysis and chi-square test confirmed age and type
of surgery, and AVN were independent risk factors of unsatisfactory hip function. Multivariate regression
analysis found ability to squat and amount of hip flexion and abduction, significantly decreased with age
at surgery; while presence of limping, amount of hip flexion, abduction, adduction and external rotation
significantly decreased with type of surgery.
Discussion: Age at surgery, type of surgery and severe AVN are independent risk factors for unsatisfactory
hip function in patients with late-detected DDH treated by open reduction. The ability to squat, the
amount of hip flexion and abduction are the main functional parameters affected by age and surgery.
Level of evidence: IV, case series
Neurotensin peptides antagonistically regulate postsynaptic dopamine D2 receptors in rat nucleus accumbens: a receptor binding and microdialysis study.
No full textAn in vitro receptor binding and in vivo microdialysis study was performed to further investigate the modulation of dopamine (DA) D2 receptors by neurotensin (NT) peptides. Saturation experiments with the D2 agonist [3H]NPA (N-propylnorapomorphine) showed that 10 nM of NT, 10 nM of neuromedin N (NN) and 1 nM of the C-terminal NT-(8–13) fragment significantly increased the KD values by 125%, 181%, and 194%, respectively without significantly affecting the Bmax value of the [3H]NPA binding sites in coronal sections of rat ventral forebrain mainly containing the nucleus accumbens (Acb) and the olfactory tubercle.
In line with the previous findings that NT can increase GABA release in the Acb and that NT receptors are not found on DA terminals in this brain region, the present in vivo microdialysis study demonstrated that local perfusion of NT (1 nM) counteracted the D2 agonist pergolide (2mgrM) induced inhibition of GABA, but not of DA release in the rat Acb. This result indicates that NT counteracts the D2 agonist induced inhibition of GABA release in the rat Acb, via an antagonistic postsynaptic NT/D2 receptor interaction as also suggested by the inhibitory regulation of D2 receptor affinity in the Acb by the NT peptides demonstrated in the present receptor binding experiments. Thus, the neuroleptic and potential antipsychotic profile of the NT peptides may involve an antagonistic NT/D2 receptor regulation in the ventral striatum
RECEPTOR-RECEPTOR INTERACTIONS AN INTEGRATIVE MECHANISM IN NERVE-CELLS
No full textSeveral lines of evidence indicate that interactions among transmission lines can take place at the level of the cell membrane via interactions among macromolecules, integral or associated to the cell membrane, involved in signal recognition and transduction. The present view will focus on this last subject, i.e., on the interactions between receptors for chemical signals at the level of the neuronal membrane (receptor-receptor interaction). By receptor-receptor interaction we mean that a neurotransmitter or modulator, by binding to its receptor, modifies the characteristics of the receptor for another transmitter or modulator. Four types of interactions among transmission Lines may be considered, but mainly intramembrane receptor-receptor interactions have been dealt with in this article, exemplified by the heteroregulation of D2 receptors via neuropeptide receptors and A2 receptors. The role of receptor-receptor interactions in the integration of signals is discussed, especially in terms of filtration of incoming signals, of integration of coincident signals, and of neuronal plasticity
A single (-)-nicotine injection causes change with a time delay in the affinity of striatal D2 receptors for antagonist, but not for agonist, nor in the D2 receptor mRNA levels in the rat substantia nigra.
No full textThe in vitro and in vivo effects of (-)-nicotine on dopamine D2 receptors in the rat neostriatum have been studied using biochemical binding, in situ hybridization and immunocytochemistry. A single i.p. injection (1 mg/kg) of (-)-nicotine resulted in a reduction of the KD value of the D2 antagonist [3H]raclopride binding sites in rat neostriatal membrane preparations at 12 h without any significant change in the Bmax value. This action of (-)-nicotine was counteracted by pretreatment 15 min earlier with the nicotine antagonist mecamylamine (1 mg/kg, i.p.). However, the KD and the Bmax values of the D2 agonist [3H]NPA binding sites in the rat neostriatal membrane preparations were not significantly affected 0.5-48 h after a single i.p. injection with 1 mg/kg of (-)-nicotine. No significant change in neostriatal D2 receptor mRNA levels was observed at any time interval after the (-)-nicotine injection. No significant change was observed in tyrosine hydroxylase (TH) immunoreactivity in either the substantia nigra or the neostriatum, nor in nigral TH mRNA levels during the time interval studied (4-24 h posttreatment). Furthermore, addition of low (10 nM) or high (1 microM) concentrations of (-)-nicotine in vitro to rat neostriatal membranes did not alter the characteristics of [3H]raclopride or [3H]NPA binding. These results indicate that a single (-)-nicotine injection can produce a selective and delayed increase in the affinity of D2 receptors for the antagonist, but not for the agonist without modifying the levels of D2 receptor mRNA, probably via the activation of central nicotinic receptors
Regular arrays of monodisperse platinum/erbium disilicide core-shell nanowires and nanoparticles on Si(001) via a self-assembled template
No full textWe have developed a process for fabricating monodisperse noble metal/rare earth disilicide core-shell nanoparticles and nanowires in regular arrays on Si( 001) with a density of 5 x 10(10)/cm(2), and over areas > 1 mm(2). Pt deposited via physical vapor deposition on a self-assembled rare earth disilicide nanowire template combined with reactive ion etching produces arrays of nanostructures. SEM images demonstrate the ability to select nanowires or nanoparticles as a function of Pt coverage. Statistical analysis of images of Pt nanoparticle arrays yield a mean feature size of 8 nm with a size variation of +/- 0.9 nm and interparticle spacing of approximately 15 nm.the Nicholas foundation for partial
funding via the Nicholas Award for Cross-Disciplinary Research and the University of California, Irvine for start up funds
- …
