241 research outputs found
Ultrastructure of the lorica of Trachelomonas Ehr. from the Colombian Amazonia
Dans le présent travail, 37 taxons appartenant au genre #Trachelomonas Ehr. (#Euglenophyta) provenant d'Amazonie Colombienne sont étudiés au microscope électronique à balayage. Nous proposons une nouvelle espèce : #T. duquei et deux nouvelles formes : #T. armata var. #gordeievii fo. #minor et #T. armata var. #spinosa n. fo. (Résumé d'auteur
Exotic polarizations of D2 branes and oblique vacua of (S)YM
We investigate the oblique vacua in the perturbed 2+1 dimensional gauge
theory living on D2 branes. The string theory dual of these vacua is expected
to correspond to polarizations of the D2 branes into NS5 branes with D4 brane
charge. We perturb the gauge theory by adding fermions masses. In the
nonsupersymmetric case, we also consider the effect of slight variations of the
masses of the scalars. For certain ranges of scalar masses we find oblique
vacua.
We show that D4 charge is an essential ingredient in understanding D2 -> NS5
polarizations. We find that some of the polarization states which appear as
metastable vacua when D4 charge is not considered are in fact unstable. They
decay by acquiring D4 charge, tilting and shrinking to zero size.Comment: 15 pages, 3 figures, LaTe
Bitangential interpolation in generalized Schur classes
Bitangential interpolation problems in the class of matrix valued functions
in the generalized Schur class are considered in both the open unit disc and
the open right half plane, including problems in which the solutions is not
assumed to be holomorphic at the interpolation points. Linear fractional
representations of the set of solutions to these problems are presented for
invertible and singular Hermitian Pick matrices. These representations make use
of a description of the ranges of linear fractional transformations with
suitably chosen domains that was developed in a previous paper.Comment: Second version, corrected typos, changed subsection 5.6, 47 page
Readthrough of nonsense mutations in Rett syndrome: evaluation of novel aminoglycosides and generation of a new mouse model
Thirty-five percent of patients with Rett syndrome carry nonsense mutations in the MECP2 gene. We have recently shown in transfected HeLa cells that readthrough of nonsense mutations in the MECP2 gene can be achieved by treatment with gentamicin and geneticin. This study was performed to test if readthrough can also be achieved in cells endogenously expressing mutant MeCP2 and to evaluate potentially more effective readthrough compounds. A mouse model was generated carrying the R168X mutation in the MECP2 gene. Transfected HeLa cells expressing mutated MeCP2 fusion proteins and mouse ear fibroblasts isolated from the new mouse model were treated with gentamicin and the novel aminoglycosides NB30, NB54, and NB84. The localization of the readthrough product was tested by immunofluorescence. Readthrough of the R168X mutation in mouse ear fibroblasts using gentamicin was detected but at lower level than in HeLa cells. As expected, the readthrough product, full-length Mecp2 protein, was located in the nucleus. NB54 and NB84 induced readthrough more effectively than gentamicin, while NB30 was less effective. Readthrough of nonsense mutations can be achieved not only in transfected HeLa cells but also in fibroblasts of the newly generated Mecp2R168X mouse model. NB54 and NB84 were more effective than gentamicin and are therefore promising candidates for readthrough therapy in Rett syndrome patients
Perioperative changes in intraabdominal pressure during abdominoplasty
A prospective clinical study of aesthetic abdominoplasty effect on perioperative changes in intraabdominal pressure was performed in 50 patients. The changes in intraabdominal pressure intraoperatively and postoperatively were examined. Abdominoplasty was found to be associated with an increase of intraabdominal pressure with the development of intraabdominal hypertension in some cases. To predict the likelihood of intraabdominal hypertension postoperatively one should use the criterion of absolute increase in the peak airway pressure over 4 cm H20 during intraoperative ventillation.Проспективное клиническое исследование по изучению влияния абдоминопластики, выполненной по эстетическим показаниям, на изменение параметров внутрибрюшного давления проведено у 50 пациентов. Изучено изменение величины внутрибрюшного давления на этапах операции и в послеоперационном периоде. Установлено, что абдоминопластика сопровождается ростом внутрибрюшного давления с развитием в ряде случаев интраабдоминальной гипертензии. Для прогнозирования вероятности развития интраабдоминальной гипертензии в послеоперационном периоде следует использовать критерий абсолютного прироста пикового давления в дыхательных путях более 4 см вод.ст. при ИВЛ на этапах операции
Algorithm of preoperative examination of breast surgery patients
The review of breast augmentation complications revealed a direct correlation between postoperative complications and elevated prolactin and thyroid-stimulating hormone levels, and the presence of autoimmune thyroiditis. An algorithm of preoperative examination of breast surgery patients has been developed, which allowed us to identify groups of patients at risk and to reduce early and late complication rates of breast augmentation.Анализ осложнений после протезирования молочных желез выявил прямую зависимость послеоперационных осложнений с повышенным уровнем пролактина и тиреотропного гормона, наличием аутоиммунного тиреоидита. Разработан алгоритм обследования пациенток на догоспитальном этапе перед маммопластикой, что позволило формировать группы риска и снизить процент ранних и поздних осложнений после протезирования молочных желез
miR-132/212 knockout mice reveal roles for these miRNAs in regulating cortical synaptic transmission and plasticity
miR-132 and miR-212 are two closely related miRNAs encoded in the same intron of a small non-coding gene, which have been suggested to play roles in both immune and neuronal function. We describe here the generation and initial characterisation of a miR-132/212 double knockout mouse. These mice were viable and fertile with no overt adverse phenotype. Analysis of innate immune responses, including TLR-induced cytokine production and IFNβ induction in response to viral infection of primary fibroblasts did not reveal any phenotype in the knockouts. In contrast, the loss of miR-132 and miR-212, while not overtly affecting neuronal morphology, did affect synaptic function. In both hippocampal and neocortical slices miR-132/212 knockout reduced basal synaptic transmission, without affecting paired-pulse facilitation. Hippocampal long-term potentiation (LTP) induced by tetanic stimulation was not affected by miR-132/212 deletion, whilst theta burst LTP was enhanced. In contrast, neocortical theta burst-induced LTP was inhibited by loss of miR-132/212. Together these results indicate that miR-132 and/or miR-212 play a significant role in synaptic function, possibly by regulating the number of postsynaptic AMPA receptors under basal conditions and during activity-dependent synaptic plasticity
Statistical Analysis of Readthrough Levels for Nonsense Mutations in Mammalian Cells Reveals a Major Determinant of Response to Gentamicin
The efficiency of translation termination depends on the nature of the stop codon and the surrounding nucleotides. Some molecules, such as aminoglycoside antibiotics (gentamicin), decrease termination efficiency and are currently being evaluated for diseases caused by premature termination codons. However, the readthrough response to treatment is highly variable and little is known about the rules governing readthrough level and response to aminoglycosides. In this study, we carried out in-depth statistical analysis on a very large set of nonsense mutations to decipher the elements of nucleotide context responsible for modulating readthrough levels and gentamicin response. We quantified readthrough for 66 sequences containing a stop codon, in the presence and absence of gentamicin, in cultured mammalian cells. We demonstrated that the efficiency of readthrough after treatment is determined by the complex interplay between the stop codon and a larger sequence context. There was a strong positive correlation between basal and induced readthrough levels, and a weak negative correlation between basal readthrough level and gentamicin response (i.e. the factor of increase from basal to induced readthrough levels). The identity of the stop codon did not affect the response to gentamicin treatment. In agreement with a previous report, we confirm that the presence of a cytosine in +4 position promotes higher basal and gentamicin-induced readthrough than other nucleotides. We highlight for the first time that the presence of a uracil residue immediately upstream from the stop codon is a major determinant of the response to gentamicin. Moreover, this effect was mediated by the nucleotide itself, rather than by the amino-acid or tRNA corresponding to the −1 codon. Finally, we point out that a uracil at this position associated with a cytosine at +4 results in an optimal gentamicin-induced readthrough, which is the therapeutically relevant variable
Pyogenic spinal infections warrant a total spine MRI
Study design: retrospective case series.
Objective: the presenting clinical symptoms of spinal infections
are often nonspecific and a delay in diagnosis can lead to adverse patient
outcomes. The morbidity and mortality of patients with multifocal spinal
infections is significantly higher compared to unifocal infections. The
purpose of the current study was to analyse the risk factors for multifocal
spinal infections.
Methods: we conducted a retrospective review of all pyogenic
non-tuberculous spinal infections treated surgically at a single tertiary
care medical center from 2006–2020. The medical records, imaging studies,
and laboratory data of 43 patients during this time period were reviewed and
analysed after receiving Institutional Review Board approval. Univariate and
multivariate analyses were performed to identify factors associated with a
multifocal spinal infection.
Results: 15 patients (35 %) had multifocal infections. In
univariate analysis, there was a significant association with chronic kidney
disease (p=0.040), gender (p=0.003), a white blood cell count
(p=0.011), and cervical (p<0.001) or thoracic (p<0.001)
involvement. In multivariate analysis, both cervical and thoracic involvement
remained statistically significant (p=0.001 and p<0.001,
respectively).
Conclusions: patients with infections in the thoracic or cervical
region are more likely to have a multifocal infection. Multifocal pyogenic
spinal infections remain a common entity and a total spine MRI should be
performed to aid in prompt diagnosis.</p
Expression of excess receptors and negative feedback control of signal pathways are required for rapid activation and prompt cessation of signal transduction
Cellular signal transduction is initiated by the binding of extracellular ligands to membrane receptors. Receptors are often expressed in excess, and cells are activated when a small number of receptors bind ligands. Intracellular signal proteins are act
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