Intraoperative assessment of colorectal anastomotic integrity: a systematic review

Background

Surgeons have attempted to minimize postoperative anastomotic complications by employing intraoperative tests and manoeuvres to assess colorectal anastomotic integrity. These have evolved over time with improvement in operative technology and techniques. This systematic review aims to examine the impact of such intraoperative assessments.

Methods

A systematic review of studies assessing intraoperative anastomotic assessments and their impact on postoperative anastomotic complications was performed. Intraoperative measures undertaken as a result of intraoperative assessments and postoperative anastomotic complications were analysed.

Results

37 Studies were identified. 13 studies evaluated basic mechanical patency tests, ten studies evaluated endoscopic visualisation techniques and 14 studies evaluated microperfusion techniques. Postoperative anastomotic complications were significantly lower in patients tested with basic mechanical patency tests compared to those untested (non-RCT: 4.1 vs. 8.1 %, p = 0.03, RCTs: 5.8 vs. 16.0 %, p = 0.024). There were no differences in postoperative anastomotic complications between tested and non-tested cohorts in non-randomised cohort studies evaluating endoscopic visualisation techniques. However, intraoperative measures taken after abnormal intraoperative tests may have reduced the number of postoperative complications. Perfusion analysis techniques are not in routine widespread clinical practice as yet, but newer techniques such as fluorescent dyes and imaging under near infrared light show technical feasibility.

Conclusions

Intraoperative colorectal anastomotic assessment has evolved together with advancement of technology in the surgical setting. Moderate benefit in terms of lower postoperative anastomotic complications has been shown with basic mechanical patency testing and more recently with intraoperative endoscopic visualisation of colorectal anastomoses. The next advance and possible introduction into routine practice may include the use of microperfusion techniques. The latest in this group of techniques, which utilise autofluorescent dyes such as Indocyanine green, hold great potential. Well-planned controlled studies or ideally, randomised controlled trials need to be conducted to further assess the benefit of these latest techniques.     

Improving the electrochemical performance of cathode composites using different sized solid electrolytes for all solid-state lithium batteries

We studied the efficiency of different particle-sized sulfide solid electrolyte-based cathode composites. First, we prepared the Li₇P₂S₈I solid electrolytes with different particle sizes through a high energy ball milling process and solution method. The structural details of the prepared solid electrolytes were studied by powder X-ray diffraction. The surface morphologies and particle size of the electrolytes were studied by field emission electron microscopy. The ionic conductivity of the prepared solid electrolytes was studied by the electrochemical impedance spectroscopy technique. Finally, we have prepared a LiNi_0.8Co_0.1Mn_0.1O₂ (NCM 811) based cathode composite and studied the electrochemical performance of the fabricated all-solid-state lithium batteries. The mixed particle-sized solid electrolyte-based cathode composite exhibited higher specific capacitance (127.2 mA h g⁻¹) than the uniform-sized solid electrolyte-based cathode composite (117.1 mA h g⁻¹). The electrochemical analysis confirmed that the sulfide solid electrolytes with mixed particle size exhibited better electrochemical performance.

Improving the electrochemical performance of a cathode composite using different sized solid electrolytes for all-solid-state lithium batteries.     

Palladium nanoparticles immobilized on polyethylenimine-derivatized gold surfaces for catalysis of Suzuki reactions: development and application in a lab-on-a-chip context

Gold surface-bound hyperbranched polyethyleneimine (PEI) films decorated with palladium nanoparticles have been used as efficient catalysts for a series of Suzuki reactions. This thin film-format demonstrated good catalytic efficiency (TON up to 3.4 × 10³) and stability. Incorporation into a quartz crystal microbalance (QCM) instrument illustrated the potential for using this approach in lab-on-a-chip-based synthesis applications.

Gold surface-bound hyperbranched polyethyleneimine (PEI) films decorated with palladium nanoparticles have been used as efficient catalysts for a series of Suzuki reactions in a lab-on-a-chip format.

Metal and metal-oxide nanostructures and nanoparticles are often key features in materials used in separation technology, biomedical devices, and catalysis.^1,2 Poor mechanical strength and a tendency to aggregate, thus reducing the surface to volume ratio, both limit their use in real-time applications.^3,4 To overcome these shortcomings, nanoparticles are often dispersed in a matrix, such as sol–gel, biopolymers, and carbon-based materials without disturbing their innate properties at nano-scale level.^5,6 Functionalized polymers have been explored extensively in this regard due to their robustness, low cost, ease of handling, and their amenability for chemical modification.^7–9Recently, we have demonstrated the immobilization of hyperbranched polyethyleneimine (PEI) hydrogels on metallic surfaces for use as antifouling surfaces.¹⁰ Owing to their hydrogelation properties, polymers of this type have proven useful in therapeutic applications, for e.g. bio-mineralization, and the formation of nanostructures.^11,12 PEI is a hyperbranched polymer containing very high densities of primary, secondary and tertiary amines, in a 1 : 2 : 1 ratio, and are capable of coordination with transition metals to form nanostructures.^13,14 Recent reports on amine functionalized polymer-supported heterogeneous catalysts for C–C coupling reactions (Table 1-SI^†) prompted us to deploy PEI as a matrix for synthesizing surface-bound palladium nanoparticles for use as catalysts of C–C coupling reactions. For catalytic applications, a miniaturized microfluidic setup, such as a lab-on-a-chip device, can significantly reduce the consumption of chemicals, catalysts, process time and be beneficial for on-site analysis.^15,16In this study, we demonstrate the use of the PEI surface-supported nanoparticles for as a support for catalysis of the Suzuki reaction the possibility for using of these Pd-nanoparticle immobilized PEI-derivatized gold surfaces for performing Suzuki reactions in a microfluidics device. Catalytic surface fabrication (Scheme 1) was performed using gold sputtered quartz surfaces (Au/quartz) that were functionalized with 11-mercaptoundecanoic acid (MuDA), and then activated and derivatization with PEI. The polymer attachment was carried out at high ionic strength (150 mM NaCl), which has been found to enhance the thickness and growth of PEI brush-like structures.¹⁰ Optimization of the Pd nanoparticle synthesis procedure was performed by varying incubation times and Pd(OAc)₂ concentrations (Table 1-SI^†). A quartz crystal microbalance (QCM) was used to monitor the amount of Pd deposited on the PEI coated Au/quartz resonators.Open in a separate windowScheme 1Palladium immobilization on polyethyleneimine coated Au/quartz surfaces.The energy dispersive X-ray (EDX) spectrum confirmed the presence of Pd in the PEI film with a distinct band at 2.8 keV (Fig. 1A). XPS spectra of the Pd-bound PEI surfaces revealed the presence of the anticipated proleptic elements (C_1s, N_1s, O_1s, Pd_3d and Au_4f) (Fig. 1A-SI^†). Deconvoluted peaks differentiated the amine N of PEI (399.8 eV) from that of the amide N (–*N–C O–, 400.8 eV) (Fig. 1B-SI^†).^17,18 Bands around 335 and 340 eV in the survey spectra correspond to the 3d_5/2 and 3d_3/2 states of the surface bound Pd.¹⁹ The deconvoluted bands at 335.3 and 338.2 demonstrated the presence of Pd(0) and Pd(ii), respectively (Fig. 1B). Importantly, peak integration showed the immobilized Pd to be predominantly in the Pd(0) state, with less than 5% present as Pd(ii).¹⁹Open in a separate windowFig. 1(A) Energy dispersive X-ray (EDX) analysis and (B) X-ray photoelectron spectra (XPS) of the palladium nanoparticle immobilized PEI coated Au/quartz surface.RAIR spectra confirmed the presence of the PEI on the gold surface based on the discernible vibrational bands of the –N–H–, –CH– and –CN– bending modes of the adsorbed PEI film (Fig. 2). Subtle differences can be observed in the RAIR spectra of the PEI before and after Pd immobilization. The band corresponding to –N–H– bending mode has been significantly red shifted emphasizing the interaction of the Pd particles with the amine moieties of the PEI film (Fig. 2, inset). This, together with the XPS data, provides evidence for the reduction of Pd(ii) to Pd(0) and its incorporation as nanoparticles into the PEI brush layer.Open in a separate windowFig. 2RAIR spectra of PEI coated Au/quartz surface before and after Pd immobilization.SEM images (Fig. 3) showed uniform long-range coating of the palladium nanoparticles on the PEI immobilized surface (PEI/Pd). The crystallinity of the Pd coated PEI surface was evaluated with powder diffraction measurements which showed characteristic peaks for Pd(111), Pd(200) and Pd(220) with Miller indices of 40, 47.2 and 68.3° (JCPDS No. 98-004-7386), respectively, again confirming the presence of Pd nanoparticles in the (0) oxidation state (curve a, Fig. 2-SI^†).Open in a separate windowFig. 3Scanning electron micrographs of (A) gold surface, (B) polyethyleneimine (PEI) film and (C) PEI-supported palladium particles fabricated on Au/quartz surfaces.The possibility of using these surfaces for catalysis of the Suzuki reaction was explored using a series of phenylboronic acids and substituted aryl halides (†). The amount of catalytic nanopalladium loaded was determined by QCM. Au/quartz surfaces coated with PEI/Pd were immersed in the reaction mixtures at 55 °C for 12 h (Section 1.7-SI^†). Reactions of aryl halides with a series of arylboronic acids offered the corresponding products in good to excellent yield (†). This negligible effect on Pd catalyst poisoning confirms the nature of the catalytic Pd exists predominantly in the (0) oxidation state.²⁰ No biphenyl product has been observed when the Suzuki reaction was performed in presence of unmodified Au/quartz surface (without PEI and Pd).Suzuki cross-coupling reactions of aryl halides with arylboronic acids using PEI/Pd as catalysts^a

Spontaneous OHSS in a Young Adolescent: A Diagnostic Dilemma

The Journal of Obstetrics and Gynecology of India -     

Targeting MYC-driven replication stress in medulloblastoma with AZD1775 and gemcitabine

Journal of Neuro-Oncology - MYC-driven medulloblastomas are highly aggressive childhood tumors with dismal outcomes and a lack of new treatment paradigms. We identified that targeting replication...     

Amyloid formation in human IAPP transgenic mouse islets and pancreas, and human pancreas, is not associated with endoplasmic reticulum stress

Aims/hypothesis  Supraphysiological levels of the amyloidogenic peptide human islet amyloid polypeptide have been associated with beta cell endoplasmic reticulum (ER) stress. However, in human type 2 diabetes, levels of human IAPP are equivalent or decreased relative to matched controls. Thus, we sought to investigate whether ER stress is induced during amyloidogenesis at physiological levels of human IAPP. Methods  Islets from human IAPP transgenic mice that develop amyloid, and non-transgenic mice that do not, were cultured for up to 7 days in 11.1, 16.7 and 33.3 mmol/l glucose. Pancreases from human IAPP transgenic and non-transgenic mice and humans with or without type 2 diabetes were also evaluated. Amyloid formation was determined histologically. ER stress was determined in islets by quantifying mRNA levels of Bip, Atf4 and Chop (also known as Ddit3) and alternate splicing of Xbp1 mRNA, or in pancreases by immunostaining for immunoglobulin heavy chain-binding protein (BIP), C/EBP homologous protein (CHOP) and X-box binding protein 1 (XBP1). Results  Amyloid formation in human IAPP transgenic islets was associated with reduced beta cell area in a glucose- and time-dependent manner. However, amyloid formation was not associated with significant increases in expression of ER stress markers under any culture condition. Thapsigargin treatment, a positive control, did result in significant ER stress. Amyloid formation in vivo in pancreas samples from human IAPP transgenic mice or humans was not associated with upregulation of ER stress markers. Conclusions/interpretation  Our data suggest that ER stress is not an obligatory pathway mediating the toxic effects of amyloid formation at physiological levels of human IAPP.     

Mesenchymal Stem Cell (MSCs) Therapy for Ischemic Heart Disease: A Promising Frontier

Although tremendous progress has been made in conventional treatment for ischemic heart disease, it still remains a major cause of death and disability. Cell-based therapeutics holds an exciting frontier of research for complete cardiac recuperation. The capacity of diverse stem and progenitor cells to stimulate cardiac renewal has been analysed, with promising results in both pre-clinical and clinical trials. Mesenchymal stem cells have been ascertained to have regenerative ability via a variety of mechanisms, including differentiation from the mesoderm lineage, immunomodulatory properties, and paracrine effects. Also, their availability, maintenance, and ability to replenish endogenous stem cell niches have rendered them suitable for front-line research. This review schemes to outline the use of mesenchymal stem cell therapeutics for ischemic heart disease, their characteristics, the potent mechanisms of mesenchymal stem cell-based heart regeneration, and highlight preclinical data. Additionally, we discuss the results of the clinical trials to date as well as ongoing clinical trials on ischemic heart disease.