Association of Portal Vein Indices with Upper Gastrointestinal Endoscopic Findings in Patients with Cirrhosis of Liver

Introduction: Upper Gastro Intestinal (UGI) bleed is major cause of mortality and admissions in cirrhotics. Timely initiation of prophylaxis reduces the burden of disease. Few endoscopists at periphery are compelled to look at other options to identify at risk patients. This study explores Portal Vein Diameter (PVD) as an option while taking clues and corrections from past studies. Aim: To identify any association between increases in portal pressure with appearance of oesophageal varices. Materials and Methods: This was an observational cross-sectional study on 75 patients of cirrhosis of liver, from November 2018 to June 2019. Baseline characteristics were noted and assessment of the severity of disease was done. Endoscopy and Portal Vein (PV) Doppler was performed in same time frame. ANOVA and unpaired t-tests were used for analysis of the collected data. A p-value <0.05 was considered significant in both the tests. Results: Grade of varices was found to have a direct relationship with portal diameter and a statistically significant inverse relationship with Portal Venous flow Velocity (PVV) (p-value 0.037). Total 28 patients had active bleed or history of UGI bleed and showed higher mean portal diameter and lower average portal velocity compared to patients without any history of variceal bleeding. A statistically significant relation was found between diameter of Portal Vein (PV) and Child-Turcotte-Pugh (CTP) grade from A to C. Patients with grade C had on an average, the biggest portal diameter and lowest PVV. Patients with Model for End-Stage Liver Disease (MELD) scores values higher than 14 and had higher mean PV diameter and a lower mean PVV. Also, hepato-fugal flow was recorded with advanced cirrhosis. Conclusion: In advanced cirrhosis, the PV Doppler can be thought of as a substitute to endoscopy in starting primary medical prophylaxis, though more extensive study needed to arrive at a definitive conclusion.

Perioperative intravenous contrast administration and the incidence of acute kidney injury after major gastrointestinal surgery: prospective, multicentre cohort study

BACKGROUND

This study aimed to determine the impact of preoperative exposure to intravenous contrast for CT and the risk of developing postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery.

METHODS

This prospective, multicentre cohort study included adults undergoing gastrointestinal resection, stoma reversal or liver resection. Both elective and emergency procedures were included. Preoperative exposure to intravenous contrast was defined as exposure to contrast administered for the purposes of CT up to 7 days before surgery. The primary endpoint was the rate of AKI within 7 days. Propensity score-matched models were adjusted for patient, disease and operative variables. In a sensitivity analysis, a propensity score-matched model explored the association between preoperative exposure to contrast and AKI in the first 48 h after surgery.

RESULTS

A total of 5378 patients were included across 173 centres. Overall, 1249 patients (23·2 per cent) received intravenous contrast. The overall rate of AKI within 7 days of surgery was 13·4 per cent (718 of 5378). In the propensity score-matched model, preoperative exposure to contrast was not associated with AKI within 7 days (odds ratio (OR) 0·95, 95 per cent c.i. 0·73 to 1·21; P = 0·669). The sensitivity analysis showed no association between preoperative contrast administration and AKI within 48 h after operation (OR 1·09, 0·84 to 1·41; P = 0·498).

CONCLUSION

There was no association between preoperative intravenous contrast administered for CT up to 7 days before surgery and postoperative AKI. Risk of contrast-induced nephropathy should not be used as a reason to avoid contrast-enhanced CT.

Anatomically realistic ultrasound phantoms using gel wax with 3D printed moulds

Here we describe methods for creating tissue-mimicking ultrasound phantoms based on patient anatomy using a soft material called gel wax. To recreate acoustically realistic tissue properties, two additives to gel wax were considered: paraffin wax to increase acoustic attenuation, and solid glass spheres to increase backscattering. The frequency dependence of ultrasound attenuation was well described with a power law over the measured range of 3–10 MHz. With the addition of paraffin wax in concentrations of 0 to 8 w/w%, attenuation varied from 0.72 to 2.91 dB cm⁻¹ at 3 MHz and from 6.84 to 26.63 dB cm⁻¹ at 10 MHz. With solid glass sphere concentrations in the range of 0.025–0.9 w/w%, acoustic backscattering consistent with a wide range of ultrasonic appearances was achieved. Native gel wax maintained its integrity during compressive deformations up to 60%; its Young’s modulus was 17.4  ±  1.4 kPa. The gel wax with additives was shaped by melting and pouring it into 3D printed moulds. Three different phantoms were constructed: a nerve and vessel phantom for peripheral nerve blocks, a heart atrium phantom, and a placental phantom for minimally-invasive fetal interventions. In the first, nerves and vessels were represented as hyperechoic and hypoechoic tubular structures, respectively, in a homogeneous background. The second phantom comprised atria derived from an MRI scan of a patient with an intervening septum and adjoining vena cavae. The third comprised the chorionic surface of a placenta with superficial fetal vessels derived from an image of a post-partum human placenta. Gel wax is a material with widely tuneable ultrasound properties and mechanical characteristics that are well suited for creating patient-specific ultrasound phantoms in several clinical disciplines.

Actinomycetes-mediated biogenic synthesis of metal and metal oxide nanoparticles: progress and challenges

Actinomycetes-mediated biogenic synthesis of metal nanoparticles and their antimicrobial activities are well documented. Actinomycetes facilitate both intracellular and extracellular metal nanoparticles synthesis and are efficient candidates for the production of polydispersed, stable and ultra-small size metal nanoparticles. Secondary metabolites and new chemical entities derived from Actinomycetes have not been extensively studied for the synthesis of metal/metal oxide nanoparticles. The present review focuses on biogenic synthesis of metal nanoparticles from Actinomycetes and the scope for exploring Actinomycetes-derived compounds (enzymes, organics acids and bioactive compounds) as metal and metal oxide reducing agents for the synthesis of desired nanoparticles. This review also focuses on challenges faced in the applications of nanoparticles and the methods to synthesize biogenic metal nanoparticles with desired physiochemical properties such as ultra-small size, large surface to mass ratio, high reactivity etc. Methods to evade their toxicity and unique interactions with biological systems to improve their chance as an alternative therapeutic agent in medical and pharmaceutical industry are also discussed.

Driving Innovation in Low Resource Settings

As of 2015, it was estimated that 400 million people lacked access to essential health services The Universal Health Coverage (UHC). Initiative aims to address this issue by delivering quality health service to people around the world whilst minimizing costs. Access to affordable medical technology is a cornerstone to this initiative. Consequently, the World Health Organisation (WHO) has developed the 'Compendium of Innovative Technologies for Low-Resource Settings' in order to highlight 127 innovations that could help to address these health issues. In low resource settings, the lack of reliable infrastructure can limit the success of medical devices, but it is clear that technology developed specifically for these settings, could have a more sustained impact. The 'Feasibility Tool' was designed by the WHOR to quantitatively analyse whether a medical device could be successfully implemented in a particular setting. The WHO has taken steps towards establishing criteria to encourage medical device innovation for appropriate and affordable technologies and local production of basic products, when feasible, in low resource settings. It is evident that encouraging this paradigms shift in our perception of medical technology development and manufacture will benefit healthcare systems around the world.

Prioritisation of vascular outpatient appointments cannot be based on referral letters alone

BACKGROUND

Vascular referrals include patients with conditions varying from varicose veins of cosmetic nuisance to patients with critical ischaemia, transient ischaemic attacks and abdominal aortic aneurysms. A large number of such referrals are received each week from general practitioners. It is important to prioritise patients with conditions that need to be dealt with quickly.

OBJECTIVE

We prospectively reviewed referral letters to two vascular units, one in South Wales and one in the Oxford region to assess whether prioritisation can be made on the basis of referral letters.

MATERIAL AND METHODS

All GP referral letters were studied for four months. Only patients with lower limb ischaemic symptoms were included. Degree of urgency requested by the GP was also noted.

RESULTS

Of 174 referrals for potential lower limb ischaemia analysed, 145 (83%) proved to be due to peripheral vascular disease. Of these 145 referrals, 72% were referred for claudication. Only 37% and 13% respectively mentioned claudication distance and/or rest pain. Risk factors with reference to diabetes, hypertension, hyperlipidaemia, ischaemic heart disease, atrial fibrillation, cerebrovascular disease and smoking were made in 19%, 43%, 23%, 23%, 10%, 14%, 31% of letters respectively. Clinical signs were poorly documented, with 90% of referrals failing to mention presence or absence of critical ischaemic signs. The GP's own assessment of urgency was not stated in 66% of letters, without which only 3% of patients were seen in the clinic within four weeks, compared with 22% in those in whom urgency was stated. Six per cent of patients when reviewed in outpatients were found to have sufficiently severe symptoms to warrant immediate admission. Regional variation was observed with 57% of Royal Glamorgan Hospital referral letters documenting degree of urgency compared with only 23% of Royal Berkshire Hospital letters (p = < 0.0001).

CONCLUSION

Most referral letters were poorly documented with regard to key symptoms, risk factors and clinical signs. The degree of urgency was often not stated. The creation of referral protocols is now being considered.

Multi-step microfluidic device for studying cancer metastasis

This paper describes a multi-step microfluidic device for studying the deformation and extravasation of primary tumor cells. Prior to extravasation, primary tumor cells undergo sequential steps of deformation through the capillaries, before adhering and transmigrating through the endothelial lining and basement membrane. To study this cascade of events, we fabricated a multi-step microfluidic device whose microgaps were coated with Matrigel to mimic the basement membrane. The microchannel was lined with human microvascular endothelial cells (HMECs) to replicate the endothelial lining. Analysis of deformation, biological and migratory capabilities of various tumor cell lines viz. HepG2, HeLa, and MDA-MB 435S were quantified using the fabricated device. After deformation, the cells' viabilities were significantly reduced and their doubling times were simultaneously increased, indicating changes in their biological capability. However, cell deformation did not significantly reduce their cell motility. Cell motility was co-assessed using the cell's migration rate and the overall population's percentage migration under various conditions (no barrier, Matrigel and Matrigel-HMEC). The device was also used to quantify the effects of Matrigel and the endothelial lining on cell migration. Our results suggest that both played an independent role in inhibiting cell extravasation, with the Matrigel significantly slowing down cell movement and the endothelial lining reducing the total number of transmigrated cells.

Matrigel coated polydimethylsiloxane based microfluidic devices for studying metastatic and non-metastatic cancer cell invasion and migration

Three-dimensional (3-D) extracellular matrices (ECM) allow complex biochemical and biophysical interactions between cells and matrices. Unlike 2-D systems, 3-D models provide a better representation of the micro and local environments in living tissues for facilitating the physiological study of cell migration. Here, we report a microfluidic device based on polydimethylsiloxane (PDMS) for monitoring 3-D cell migration across ECM-coated microgaps with real-time light microscopy. We tracked the migration of the invasive MDA-MB-231 (mammary carcinoma) cells and mapped out their migration paths. It enabled us to quantify the percentage of migrated cells as well as migration information of individual cells. This wide spectrum of data acquisition is vital for elucidating the migration capabilities of different type of cells and to understand the basic mechanism involved in cancer metastasis.

A quantitative observation and imaging of single tumor cell migration and deformation using a multi-gap microfluidic device representing the blood vessel

A microfluidic device was developed for quantifying the migratory and deformability capabilities of a single tumor cell using direct imaging. It was fabricated using photolithography and is made of polydimethysiloxane. Chemotaxis approach was used for directing cell movement, using 10 microm microgaps to restrict the migration to a single cell. Each cell's migration rate is quantified as a measure of its distance traveled over time taken. Real-time recording of cell deformation under physiological flow was performed, and the elongation index and surface area change of the cells were compared. Three human tumor cell lines viz. HepG2, HeLa and MDA-MB-435S were used to verify the operation and methodology of the device. Their migration rates ranged from 5 to 15 microm/h, consistent with other scientific reports. By reducing the microgap width to 3 microm, it was found that the cells moved along the row of microgaps but were unable to migrate across the microgaps. Subsequent deformation of the cells through the gaps further showed that their migratory capability might be governed by their deformation ability and the deformation stress on their membranes. The strategy of targeting cancer cell membrane for rupture may provide a therapy for metastasis. Being a valuable tool for rapid quantification of a single cell's migratory capability, this device should be helpful for pharmacologic and drug screening, investigation of factors that regulate cell migration and deformation.

Role of silver ions in destabilization of intermolecular adhesion forces measured by atomic force microscopy in Staphylococcus epidermidis biofilms

In this paper, we report on the potential use of atomic force microscopy (AFM) as a tool to measure the intermolecular forces in biofilm structures and to study the effect of silver ions on sessile Staphylococcus epidermidis cell viability and stability. We propose a strategy of destabilizing the biofilm matrix by reducing the intermolecular forces within the extracellular polymeric substances (EPSs) using a low concentration (50 ppb) of silver ions. Our AFM studies on the intermolecular forces within the EPSs of S. epidermidis RP62A and S.epidermidis 1457 biofilms suggest that the silver ions can destabilize the biofilm matrix by binding to electron donor groups of the biological molecules. This leads to reductions in the number of binding sites for hydrogen bonds and electrostatic and hydrophobic interactions and, hence, the destabilization of the biofilm structure.

Scanning tunneling microscopy and spectroscopy investigations of QCA molecules

Quantum-dot cellular automata (QCA), a computation paradigm based on the Coulomb interactions between neighboring cells. The key idea is to represent binary information, not by the state of a current switch (transistor), but rather by the configuration of charge in a bistable cell. In its molecular realization, the QCA cell can be a single molecule. QCA is ideally suited for molecular implementation since it exploits the molecule's ability to contain charge, and does not rely on any current flow between the molecules. We have examined using an UHV-STM some of the QCA molecules like silicon phthalocyanines and Fe-Ru complexes on Au (111) and Si (111) surfaces, which are suitable candidates for the molecular QCA approach.