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Republication de : Positive and negative post stapedotomy effects on cervical VEMP recordings; a STROBE analysis

The primary goal of the present study was to compare the pre- and post-stapedotomy elicitation and waveform characteristics of both air- and bone-conduction (AC-, BC-) cervical vestibular evoked myogenic potentials (cVEMPs) through an individualized approach. A possible association between audiological characteristics, such as AC- and BC- pure tone audiometry thresholds and air-bone gap and the production of cVEMPs before and after stapedotomy was also investigated. Twenty-five ears were subjected to full audiological evaluation as well as AC- and BC-cVEMPs pre- and post-stapedotomy. Four subgroups were studied; consistently present/absent, post-operatively disappeared and restored cVEMPs. Post-stapedotomy changes in cVEMP elicitability did not reach significance for either AC-cVEMP (OR = 5.41, 95% CI 0.88–33.36, P = 0.06) or BC-cVEMP (OR = 2.40, 95% CI 0.42–13.60, P = 0.3). Normal or abnormal AC-cVEMPs were equally subject to post-operative changes (OR = 1.95, 95% CI 0.32–12.01, P = 0.5), as were BC-cVEMPs (OR = 3.75, 95% CI 0.66–21.25, P = 0.1). Neither the audiological characteristics nor the surgical outcome, in terms of ABG results, were relevant to the presence or absence of AC- and BC-cVEMPs before or after stapedotomy. The presumed changes brought to the sacculus by stapedotomy are minor and beyond the diagnostic abilities of either AC-cVEMPs or BC-cVEMPs, both in terms of cVEMPs elicitability and waveform characteristics. In individual cases, however, which may deserve further investigation, cVEMPs may reappear or disappear after stapedotomy probably following minor changes toward a lower or higher vestibular system resistance for pressure and sound transmission.

Positive and negative post stapedotomy effects on cervical VEMP recordings; a STROBE analysis

AimsThe primary goal of the present study was to compare the pre- and post-stapedotomy elicitation and waveform characteristics of both air- and bone-conduction (AC-, BC-) cervical vestibular evoked myogenic potentials (cVEMPs) through an individualized approach. A possible association between audiological characteristics, such as AC- and BC- pure tone audiometry thresholds and air-bone gap and the production of cVEMPs before and after stapedotomy was also investigated. Material and methodsTwenty-five ears were subjected to full audiological evaluation as well as AC- and BC-cVEMPs pre- and post-stapedotomy. Four subgroups were studied; consistently present/absent, post-operatively disappeared and restored cVEMPs. ResultsPost-stapedotomy changes in cVEMP elicitability did not reach significance for either AC-cVEMP (OR=5.41, 95% CI 0.88–33.36, P=0.06) or BC-cVEMP (OR=2.40, 95% CI 0.42–13.60, P=0.3). Normal or abnormal AC-cVEMPs were equally subject to post-operative changes (OR=1.95, 95% CI 0.32–12.01, P=0.5), as were BC-cVEMPs (OR=3.75, 95% CI 0.66–21.25, P=0.1). Neither the audiological characteristics nor the surgical outcome, in terms of ABG results, were relevant to the presence or absence of AC- and BC-cVEMPs before or after stapedotomy. ConclusionsThe presumed changes brought to the sacculus by stapedotomy are minor and beyond the diagnostic abilities of either AC-cVEMPs or BC-cVEMPs, both in terms of cVEMPs elicitability and waveform characteristics. In individual cases, however, which may deserve further investigation, cVEMPs may reappear or disappear after stapedotomy probably following minor changes toward a lower or higher vestibular system resistance for pressure and sound transmission.

How early is early? Effect of oxybutynin on bladder dynamics within the first year of life in patients with spina bifida

Early proactive treatment of patients with high-risk neurogenic bladder from spina bifida (SB) may preserve renal function and decrease the need for bladder augmentation later in life. Timing of initiation of anticholinergic therapy (AC) medication and clean intermittent catheterization (CIC) is variable and based on imprecise studies. The authors hypothesized that initiation of AC after the initial video-urodynamic study (VUDS) may benefit bladder capacity even in children who do not meet the standard hostile criteria for starting AC. A retrospective review of a prospectively maintained VUDS database from August 2015 to March 2019 was performed. Patients with SB who had undergone initial VUDS between 1 and 7 months of age and had a subsequent follow-up study between 9 and 18 months of age were included. Multiple VUDS and clinical parameters including expected bladder capacity, actual capacity reached, pressure at actual capacity, presence of detrusor overactivity, presence of urinary tract dilation and reflux, and whether or not AC was started were extracted and compared. P-value of <0.05 was considered statistically significant. A total of 69 patients completed an initial study at median age of 2 months, and follow-up study at median age of 13 months. Anticholinergic therapy was started in 21 patients (10F, 11M). Decision to initiate AC was at discretion of the attending pediatric urologist performing the VUDS in real time. Changes between the initial and repeat VUDS are listed in the summary table below. Adverse effects of AC were reported in 25% (5/21) patients: urinary retention/UTIs (3), allergic reaction (1), and fatigue (1). The authors findings suggest that AC stabilizes storage pressure for those who initially have a higher storage pressure, while in those with initial low storage pressures, storage pressures worsened over time in the absence of AC. Patients started on AC experienced a faster rate of increase in bladder capacity. Limitations to this study included the unknown long term and sustainability of the improvement in bladder parameters, the lack of uniform criteria for the initiation of AC or CIC, and an unknown long-term degree of upper tract protection. This study found early initiation of AC in SB at 2 months of age had significant positive effects on growth of bladder capacity and stabilization of storage pressure. However, long-term effects of AC are still undetermined, and thus, longitudinal studies are needed to understand the precise indications for initiation of early AC treatment.

Effect of AC on stress corrosion cracking behavior and mechanism of X80 pipeline steel in carbonate/bicarbonate solution

The influence of various AC current densities on stress corrosion cracking behavior and mechanism of X80 pipeline steel was investigated in carbonate/bicarbonate solution by polarization curves and slow strain rate tensile tests. With the increasing AC current density, the SCC susceptibility of the steel increases, especially at high AC current density. A significant difference in the SCC behavior and mechanism is found for the steels with or without AC application. In the absence of AC, the fracture mode is intergranular and the mechanism is attributed to anodic dissolution. Under AC application, the cracks propagation is transgranular, and the mechanism is mixed controlled by both anodic dissolution and hydrogen embrittlement.

In vivo proton MR spectroscopy in uterine abscesses

It is important to make a rapid diagnosis to provide appropriate treatment, however, specific diagnosis of causative organisms of pelvic abscesses on conventional MR imaging is difficult. MR spectroscopy provides metabolic information noninvasively, and has the potential to characterize etiology of the abscesses. The presence of acetate (Ac) peak with or without succinate (Suc) peak may suggest anaerobic bacterial infection, whereas the absence of Ac and Suc peaks in the spectra may suggest aerobic infection. This report describes two cases of uterine pyogenic abscesses, which showed Ac and Suc peaks on in vivo MR spectroscopy.

Early and multiple Ac transpositions in rice suitable for efficient insertional mutagenesis.

A GFP excision assay was developed to monitor the excision of Ac introduced into rice by Agrobacterium-mediated transformation. The presence of a strong double enhancer element of the CaMV 35S promoter adjacent to the Ac promoter induced very early excision, directly after transformation into the plant cell, exemplified by the absence of Ac in the T-DNA loci. Excision fingerprint analysis and characterization of transposition events from related regenerants revealed an inverse correlation between the number of excision events and transposed Ac copies, with single early excisions after transformation generating Ac amplification. New transpositions were generated at a frequency of 15-50% in different lines, yielding genotypes bearing multiple insertions, many of which were inherited in the progeny. The sequence of DNA flanking Ac in three representative lines provided a database of insertion tagged sites suitable for the identification of mutants of sequenced genes that can be examined for phenotypes in a reverse genetics strategy to elucidate gene function. Remarkably, two-thirds of Ac tagged sites showing homology to sequences in public databases were in predicted genes. A clear preference of transposon insertions in genes that are either predicted by protein coding capacity or by similarity to ESTs suggests that the efficiency of recovering knockout mutants of genes could be about three times higher than random. Linked Ac transposition, suitable for targeted tagging, was documented by segregation analysis of a crippled Ac element and by recovery of a set of six insertions in a contiguous sequence of 70 kb from chromosome 6 of rice.

Activated Carbon and Carbon Black Catalyzed Transformation of Aqueous Ozone into OH-Radicals

In an ozone-containing water a suspension of a few milligrams per liter of activated carbon (AQ or carbon black (CB) initiates a radical-type chain reaction that then proceeds in the aqueous phase and accelerates the transformation of O3 into secondary radicals, such as hydroxyl radicals (°OH). This results in an Advanced Oxidation Process (AOP) that is similar to an O3-based AOP involving application of H2O2 or UV-irradiation. We have studied these phenomena by observing the effect of suspensions of AC and CB on the rate of transformation of O3 in lakewater and in well-characterized solutions. In addition, the stoichiometric yield factor of the AC-catalyzed conversion of O3, into °OH has been shown to be comparable to that which is achieved by a slower process in the absence of AC. This comparison has been based on the measured depletion of an O3-resistant organic °OH probe that was added as a trace reference compound and that competed with a kinetic excess of solutes that controlled the lifetime of °OH. The AC-catalyzed transformation of O3 into °OH for creating an O3-based AOP may be of practical interest to water utilities as an alternative to extended reaction times, to hydrogen peroxide addition, or to UV-catalyzed transformation of O3. We propose the name “Carbozone Process” for this new type of AOP.

Novel synthesis of phenol derivatives by palladium-catalyzed cyclocarbonylation of 2,4-pentadienyl acetates

Phenyl acetates were selectively obtained in good yields by cyclocarbonylation of 2,4-pentadienyl acetates in the presence of NEt 3 , Ac 2 O, and a catalytic amount of palladium complexes such as PdCl 2 (PPh 3 ) 2 at 120-140 o C under 50 atm of CO. No five-membered ring products were observed. A platinum complex PtCl 2 (PPh 3 ) 2 was also effective as a catalyst. The reaction of 5-phenyl-2,4-pentadienyl bromide with M(CO)(PPh 3 ) 3 (M=Pd or Pt) under CO gave the corresponding 6-phenyl-3,5-hexadienoyl complexes in a high yield, which in turn afforded 2-acetoxybiphenyl in 41-51% yield on heating to 160 o C under 50 atm of CO in the presence of NEt 3 and Ac 2 O. Similar 3,5-hexadienoyl complexes ere proposed to be intermediates in the catalytic cyclocarbonylation of 2,4-pentadienyl acatates. On the other hand, PdCl 2 (PPh 3 ) 2 -catalyzed carbonylation of o-(bromomethyl)(1-alkenyl)benzenes in the presence of NEt 3 and Ac 2 O gave 2-naphtyl acetates in moderate yields, while the reaction in the absence of Ac 2 O gave five-membered ring products such as 2-indanones or a tricyclic lactone by incorporation of one or two CO molecules, respectively

AC-Induced Pitting of Tin-Coated Copper Utility Cables

Abstract Laboratory exposure tests involving chemicals commonly found in soil and an AC current flow between a tin-coated copper electrode and a surrounding electrolyte were conducted to provide data regarding the mechanism and rate of concentric neutral corrosion encountered in underground rural distribution systems. Experimental data supportive of an AC-induced pit initiation mechanism followed by autocatalytic pit growth are presented. In the absence of AC, the potential of tin-coated wire stabilizes at a more negative potential than that of bare copper wire, thus providing cathodic protection to exposed copper. In the presence of an AC signal, the potential of the tin-coated wire shifts to a more positive potential than that of the bare wire, indicating that AC-induced resistive currents on tin-coated samples passivate the tin coating, rendering it cathodic to the underlying copper. The large cathodic area leads to rapid pitting of the copper substrate at coating imperfections.

Changes in state of the Wx-m5 allele of maize are due to intragenic transposition of Ds.

The molecular basis for the unusual phenotype conditioned by the waxy(Wx)-m5 Ds allele has been elucidated. Unlike most Ds alleles, Wx-m5 is phenotypically wild-type in the absence of Ac. We find that the Wx-m5 gene contains a 2-kb Ds element at -470 relative to the start of Wx transcription, representing the most 5' insertion of any transposable element allele characterized to date in plants. Despite its wild type phenotype, Wx-m5 has reduced levels of Wx enzymatic activity indicating that Ds insertion influences Wx gene expression. In the presence of Ac, Wx-m5 kernels have sectors of null expression on a wild-type background and give rise to stable wx and unstable wx-m germinal derivatives. Seventeen of 20 derivatives examined are wx-m alleles and at least 15 of these appear to result from intragenic transposition of Ds from -470 to new sites within the Wx gene. Three wx-m alleles contain two Ds elements, one at -470 and a second in Wx coding sequences. Surprisingly, only 3 out of 20 derivatives are stable wx mutants and these have sustained gross rearrangements of Wx and flanking sequences. For most other maize transposable element alleles somatic sectors and germinal derivatives usually arise following element excision or deletions of element sequences. In contrast, element insertion following intragenic transposition is apparently responsible for most of the somatic sectors and germinal derivatives of Wx-m5.

Human T cell clones with [formula omitted] and [formula omitted] receptors are differently stimulated by monoclonal antibodies to CD2

Requirements for stimulating autocrine proliferation of human T cell clones expressing either α β or γ δ antigen receptors via the “alternative” CD2 pathway have been examined using a large set of monoclonal antibodies (mAb). In the presence of autologous accessory cells (AC, B-lymphoblastoid cell lines) 2 of 13 single CD2 mAb (CLB-T11.1/1 and 6F10.3) stimulated proliferation of γ δ but not α β cells. Interleukin (IL) 1 or IL 6 did not substitute for AC in stimulating γ gd clones. Addition of CD28 mAb YTH 913.12 with the CD2 mAb did not result in stimulation of any α gb clones. In the absence of AC, none of the CD2 mAb singly could stimulate any T cell clones, but pairs of mAb directed to different epitopes of CD2 (CLB-T11.1/ 1 + CLB- T1 1.2/1 or 6F10.3 + 39C1.5) stimulated both α β and α δ clones. In both cases, stimulation was reduced by the presence of CD3 mAb. These results confirm that the established AC-independent alternative pathway of T cell activation, which requires binding of two separate epitopes of CD2, operates in both γ δ and α β T cells, and further suggest that an additional pathway initiated by binding of a single CD2 epitope in the presence of AC is exclusively operational in γ gd cells.

Promotory and inhibitory effects of activated charcoal on microspore embryogenesis in Datura metel

Activated charcoal (AC, 0.25–1%) added to Murashige and Skoog medium supplemented with coconut milk (CM, 15%), inhibited the androgenic response of Datura metel anthers excised from fresh as well as cold pretreated buds (3 days at 3±2 °C). The inhibitory effect of AC was directly proportional to its concentration for fresh as well as cold pretreated explants. This indicated that either AC itself is toxic or reduces the response by adsorbing some substance(s) from explants and/or from the medium. It was thought that AC is probably reducing the response by adsorbing some active component(s) of CM. This possibility was tested by studying the effect of different concentrations of CM in the presence (1%) and absence of AC. It was found that AC reduced the response only in the presence of CM, which was below the level recorded for anthers incubated on basal medium alone. Individually, both CM and AC enhanced the plantlet yield.

Ds-INDUCED ALLELES AT THE OPAQUE-2 LOCUS OF MAIZE

Transposon mutagenesis has been used to isolate mutable alleles at the Opaque-2 (O2) locus of maize. Plants with the Activator-Dissociation (Ac-Ds) system of transposable elements and O2 were crossed as males to a stable o2 tester line. Among a population of 200,000 kernels, 198 exceptional kernels with somatic instability were recovered. In four cases, designated O2-m1, o2-m2, O2-m3 and O2-m4, variegated phenotypes appeared in F(2) and subsequent generations. Genetic analyses indicated that the presence of Ds near or within the O2 gene was responsible for the observed somatic instability at the O2 locus. The phenotypes of the newly induced alleles were of two types. Alleles O2-m1, O2-m3 and O2-m4, in the absence of Ac, were characterized by kernel phenotypes indistinguishable from the wild type; in the presence of Ac they generated kernels with opaque sectors interspersed within a vitreous background. In contrast, the mutable allele o2-m2, in the absence of Ac, was characterized by kernels with a recessive phenotype similar to o2 recessive mutants. In the presence of Ac, it reverted somatically to wild-type-producing kernels with vitreous spots in an o2 background. The association of the Ds element with the O2 locus may prove a valuable tool directed to the isolation of DNA fragments bearing the O2 gene.

Horrors of topology without 𝐴𝐶: a nonnormal orderable space

In the absence of AC there can be a space which is not normal, yet which is orderable and is the topological sum of countably many compact countable metrizable spaces.

Absence of a detectable change in Ds at the A1 locus in maize following mutagenic treatments.

Various mutagenically-effective treatments for Sh2locus failed to produce any back mutation of the closely linked [Formula: see text] marker complex. Nor were any Ac-like elements generated. An excision-repair model was proposed to explain the stability of Ds mutations in the absence of Ac and its high mutability in the presence of Ac. A number of other observations on mutable loci in maize were also explained on the basis of this scheme.