Role of retrograde dilatation in the management of pharyngo-esophageal corrosive strictures

Pharyngo-esophageal corrosive stricture is a complex clinical scenario. If an esophageal opening cannot be found orally through endoscopy, a retrograde approach with a mini-laparotomy and gastrostomy should be attempted. This study primarily aimed at defining the role of preoperative retrograde dilatation of pharyngo-esophageal corrosive strictures. A retrospective analysis of 51 cases of pharyngo-esophageal corrosive strictures identified between 1997-2005 was performed. The demographic details were analyzed. The details of the injury to the pharynx either in isolation or in combination were noted and the management details were recorded. In 21 patients preoperative retrograde dilatation was considered and the technique was successful in 14 (Group I). In seven the technique failed (Group II) and these patients underwent transhiatal resection and gastric pull-through and/or retrosternal pharyngocoloplasty. In Group I patients the postoperative stay was significantly less than in Group II (12 +/- 2.03 days vs. 18 +/- 4.32 days; p = 0.001) Recurrent aspiration, respiratory tract infections, choking sensation and the need for tracheostomy were less frequent in Group I. The overall functional assessment was good in Group I. For treatment of pharyngo-esophageal obstruction, if antegrade dilatation is not possible due to technical reasons, retrograde dilatation is a viable option before opting for organ replacement/bypass procedures. There is no best replacement of the native organ to maintain quality of life.     

Electron diffraction studies of light-induced conformational changes in the Leu-93 → Ala bacteriorhodopsin mutant

We previously have presented evidence for prominent structural changes in helices F and G of bacteriorhodopsin during the photocycle. These changes were determined by carrying out electron diffraction analysis of illuminated two-dimensional crystals of wild-type bacteriorhodopsin or the Asp-96 → Gly mutant that were trapped at a stage in the photocycle after light-driven proton release, but preceding proton uptake from the aqueous medium. Here, we report structural analysis of the long-lived O intermediate observed in the photocycle of the Leu-93 → Ala mutant, which accumulates after the release and uptake of protons, but before the reisomerization of retinal to its initial all-trans state. Projection Fourier difference maps show that upon illumination of the Leu-93 → Ala mutant, significant structural changes occur in the vicinity of helices C, B, and G, and to a lesser extent near helix F. Our results suggest that (i) all four helices that line the proton channel (B, C, F, and G) participate in structural changes during the late stages of the photocycle, and (ii) completion of the photocycle involves significant conformational changes in addition to those that are associated with steps in proton transport.     

Estrogen-eluting, phosphorylcholine-coated stent implantation is associated with reduced neointimal formation but no delay in vascular repair in a porcine coronary model.

Estrogen can inhibit intimal proliferation and accelerate endothelial regeneration after angioplasty. This suggests that estrogen may prevent in-stent restenosis. Unlike other therapies to prevent restenosis, estrogen may also not delay endothelial regrowth, thereby avoiding the risk of late stent thrombosis. The purpose of this work was to determine the effect of a 17beta-estradiol-eluting stent on neointimal formation in a porcine model. Each artery of six pigs was randomized to either a control, low-dose, or high-dose 17beta-estradiol-eluting stent. All animals were sacrificed at 30 days for histopathological analysis. There was a 40% reduction in intimal area in the high-dose stents compared with control stents (2.54 +/- 1.0 vs. 4.13 +/- 1.1 mm(2), for high dose vs. control, respectively; P < 0.05). There was complete endothelial regeneration at 30 days and similar inflammatory response to stenting on histopathology in all the stent groups. This is the first study to show that 17beta-estradiol-eluting stents are associated with reduced neointimal formation without affecting endothelial regeneration in the pig model of in-stent restenosis. Estrogen-coated stents may have a potential benefit in the prevention and treatment of in-stent restenosis.     

Subtype B and subtype C HIV type 1 recombinants in the northeastern state of Manipur, India

The predominant HIV-1 strain circulating in India is subtype C. However, subtype A and B strains of HIV-1 have also been reported in India. In 1999, the first A/C recombinant strain was reported from Pune in India. Intravenous drug users (IVDUs) from the northeastern region of India have a high HIV-1 seroprevalence. Studies carried out in intravenous drug users in the northeastern region of India have shown that HIV-1 subtype C is the predominant strain infecting IVDUs. Fourteen blood samples were collected from HIV-1-infected individuals from the northeastern region of India and screened by env and gag heteroduplex mobility assays (HMA). Where the env and gag HMA results from a sample yielded different subtypes, sequencing of env and gag PCR products was carried out to confirm the presence of HIV-1 recombinants. Of the 14 samples subtyped, nine samples belonged HIV-1 subtype C (gag C/env C), one to HIV-1 subtype B (gag B/env B), and the remaining were B/C recombinants (gag C/env B). This is the first report of HIV-1 B/C recombinants from India.     

Predictors of thrombotic complications after placement of the flexible coil stent

The balloon-expandable, stainless steel, flexible coil stent is a useful device for managing acute or threatened closure after percutaneous transluminal coronary angioplasty.^1–5 Use of the device is associated with thrombosis of the stented vessel in a small but important group of patients.^3,6–10 The clinical, angiographic, and procedural factors associated with stent thrombosis with this device are still unknown. The objective of this study was to define predictors of stent thrombosis occurring within the ftrst month after stenting with this device.     

Cephalometric evaluation of the pharyngeal airway space after orthognathic surgery and distraction osteogenesis of the jaw bones

Objective:

Orthognathic surgeries and distraction osteogenesis (DO) of the jaw bones cause a change in the pharyngeal airway space (PAS). The aim of our study was to evaluate the magnitude of changes occurring in the pharyngeal airway after mandibular set-back surgeries and DO of maxilla/mandible.

Materials and Methods:

The study undertaken was a retrospective cephalometric study. Subjects included in our study had undergone mandibular set-back surgery or DO of maxilla/mandible. Lateral cephalograms of the subjects taken pre-operatively (T0), immediate post-operatively (T1) and after a minimum follow-up period of 6 months (T2) were studied. The cephalograms were traced manually and the following parameters were evaluated: Surface area of the PAS, pharyngeal airway width at the level of the base of the tongue, position of the hyoid bone and the tongue. Repeated measure ANOVA test was done to assess the presence of any significant changes in the proposed parameters at T0, T1 and T2. A correlation analysis was made between the mandibular/maxillary movements and the corresponding changes in the PAS.

Results:

Surgical movements of maxilla and mandible do have an effect on the pharyngeal airway.

Conclusion:

It was clearly evident that the effects of mandibular movements on the PAS and the hyoid bone is more significant than the maxillary movements.KEY WORDS: Distraction osteogenesis, orthognathic surgery, pharyngeal airway space     

cIMPACT‐NOW update 7: advancing the molecular classification of ependymal tumors

Advances in our understanding of the biological basis and molecular characteristics of ependymal tumors since the latest iteration of the World Health Organization (WHO) classification of CNS tumors (2016) have prompted the cIMPACT‐NOW group to recommend a new classification. Separation of ependymal tumors by anatomic site is an important principle of the new classification and was prompted by methylome profiling data to indicate that molecular groups of ependymal tumors in the posterior fossa and supratentorial and spinal compartments are distinct. Common recurrent genetic or epigenetic alterations found in tumors belonging to the main molecular groups have been used to define tumor types at intracranial sites; C11orf95 and YAP1 fusion genes for supratentorial tumors and two types of posterior fossa ependymoma defined by methylation group, PFA and PFB. A recently described type of aggressive spinal ependymoma with MYCN amplification has also been included. Myxopapillary ependymoma and subependymoma have been retained as histopathologically defined tumor types, but the classification has dropped the distinction between classic and anaplastic ependymoma. While the cIMPACT‐NOW group considered that data to inform assignment of grade to molecularly defined ependymomas are insufficiently mature, it recommends assigning WHO grade 2 to myxopapillary ependymoma and allows grade 2 or grade 3 to be assigned to ependymomas not defined by molecular status.     

Insight into the PEC and interfacial charge transfer kinetics at the Mo doped BiVO4 photoanodes

BiVO₄ is a promising photoanode material for the photoelectrochemical (PEC) oxidation of water; however, its poor charge transfer, transport, and slow surface catalytic activity limit the expected theoretical efficiency. Herein, we have investigated the effect of Mo doping on SnO₂ buffer layer coated BiVO₄ for PEC water splitting. SnO₂ and Mo doped BiVO₄ layers are coated with layer by layer deposition through a precursor solution based spin coating technique followed by annealing. At 5% doping of Mo, the sample (SBM5) shows a maximum current density of 1.65 mA cm⁻² at 1.64 V vs. RHEl in 0.1 M phosphate buffer solution under AM 1.5 G solar simulator, which is about 154% improvement over the sample without Mo (SBM0). The significant improvement in the photocurrent upon Mo doping is due to the improvement of various bulk and interfacial properties in the materials as measured by UV-vis spectroscopy, electrochemical impedance spectroscopy (EIS), Mott–Schottky analysis, and open-circuit photovoltage (OCPV). The charge transfer kinetics at the BiVO₄/electrolyte interface are investigated to simulate the oxygen evolution process in photoelectrochemical water oxidation in the feedback mode of scanning electrochemical microscopy (SECM) using 2 mM [Fe(CN)₆]³⁻ as the redox couple. SECM investigation reveals a significant improvement in effective hole transfer rate constant from 2.18 cm s⁻¹ to 7.56 cm s⁻¹ for the hole transfer reaction from the valence band of BiVO₄ to [Fe(CN)₆]⁴⁻ to oxidize into [Fe(CN)₆]³⁻ with the Mo doping in BiVO₄. Results suggest that Mo⁶⁺ doping facilitates the hole transfer and suppresses the back reaction. The synergistic effect of fast forward and backward conversion of Mo⁶⁺ to Mo⁵⁺ expected to facilitate the V⁵⁺ to V⁴⁺ which has an important step to improve the photocurrent.

BiVO₄ is a promising photoanode material for the photoelectrochemical (PEC) oxidation of water; however, its poor charge transfer, transport, and slow surface catalytic activity limit the expected theoretical efficiency.     

mGluR5 and GABAA receptor‐specific parametric PET atlas construction—PET/MR data processing pipeline,validation, and application

The glutamate and γ‐aminobutyric acid neuroreceptor subtypes mGluR₅ and GABA_A are hypothesized to be involved in the development of a variety of psychiatric diseases. However, detailed information relating to their in vivo distribution is generally unavailable. Maps of such distributions could potentially aid clinical studies by providing a reference for the normal distribution of neuroreceptors and may also be useful as covariates in advanced functional magnetic resonance imaging (MR) studies. In this study, we propose a comprehensive processing pipeline for the construction of standard space, in vivo distributions of non‐displaceable binding potential (BP _ND), and total distribution volume (V _T) based on simultaneously acquired bolus‐infusion positron emission tomography (PET) and MR data. The pipeline was applied to [¹¹C]ABP688‐PET/MR (13 healthy male non‐smokers, 26.6 ± 7.0 years) and [¹¹C]Flumazenil‐PET/MR (10 healthy males, 25.8 ± 3.0 years) data. Activity concentration templates, as well as V _T and BP _ND atlases of mGluR₅ and GABA_A, were generated from these data. The maps were validated by assessing the percent error δ from warped space to native space in a selection of brain regions. We verified that the average δ_ABP = 3.0 ± 1.0% and δ_FMZ = 3.8 ± 1.4% were lower than the expected variabilities σ of the tracers (σ_ABP = 4.0%–16.0%, σ_FMZ = 3.9%–9.5%). An evaluation of PET‐to‐PET registrations based on the new maps showed higher registration accuracy compared to registrations based on the commonly used [¹⁵O]H₂O‐template distributed with SPM12. Thus, we conclude that the resulting maps can be used for further research and the proposed pipeline is a viable tool for the construction of standardized PET data distributions.