Expanding the scope of self-assembled supramolecular biosensors: a highly selective and sensitive enzyme-responsive AIE-based fluorescent biosensor for trypsin detection and inhibitor screening.

Trypsin, a pancreatic enzyme associated with diseases like pancreatic cancer and cystic fibrosis, requires effective diagnostic tools. Current detection systems seldom utilize macrocyclic molecules and tetraphenyl ethylene (TPE) derivative-based supramolecular assemblies, known for their biocompatibility and aggregation-induced emission (AIE) properties, for trypsin detection. This study presents an enzyme-responsive, AIE-based fluorescence 'Turn-On' sensing platform for trypsin detection, employing sulfated-ß-cyclodextrin (S-ßCD), an imidazolium derivative of TPE (TPE-IM), and protamine sulfate (PrS). The anionic S-ßCD and cationic TPE-IM formed a strongly fluorescent supramolecular aggregation complex in an aqueous buffer. However, PrS suppresses fluorescence because of its strong binding affinity with S-ßCD. The non-fluorescent TPE-IM/S-ßCD/PrS supramolecular assembly system exhibits trypsin-responsive properties, as PrS is a known trypsin substrate. Trypsin restores fluorescence in the TPE-IM/S-ßCD system through the enzymatic cleavage of PrS, correlating linearly with trypsin catalytic activity in the 0-10 nM concentration range. The limit of detection is 10 pM. This work contributes to the development of self-assembled supramolecular biosensors using charged TPE derivatives and ß-cyclodextrin-based host-guest chemistry, offering an innovative fluorescence 'Turn-On' trypsin sensing platform. The sensing system is highly stable under various conditions, selective for trypsin, and demonstrates potential for biological analysis and disease diagnosis in human serum. Additionally, it shows promise for the screening of trypsin inhibitors.

A turn-on fluorescence sensor for detection of heparinase with heparin templated aggregation of tetracationic porphyrin derivative.

Heparinase is the only mammalian endoglycosidase that breaks down the commonly used blood-anticoagulant heparin into therapeutically relevant low-molecular-weight-heparin. Importantly, heparinase has been considered a malignant disease diagnostic marker. Thus, it is essential to develop detection scheme for heparinase. However, optical methods for heparinase determination are limited. In the present work, we report a turn-on fluorescence sensor for detection of heparinase that utilizes heparin-templated aggregation of a tetra-cationic porphyrin derivative, TMPyP4+, as a sensing framework. Heparinase cleaves the glycosidic linkage between hexosamine and uronic acid in the structure of heparin to destroy its polyelectrolytic nature that originally causes the aggregation of TMPyP4+. Thus, heparinase leads to dissociation of TMPyP4+ aggregates and generates an optical signal. This system leads to a sensitive and selective response towards heparinase with a Limit of Detection (LOD) of 0.3 pmol/L. Further, the same system is demonstrated to sense a trace amount of Oversulfated Chondrootin Sulphate (OSCS) in heparin, which is a heparin adulterant, by utilizing the fact that OSCS serves as an inhibitor for heparinase activity, which leads to reverse modulation in the photo-physical features of the monomer/aggregate equilibrium of the TMPyP4+-heparin-heparinase system. The sensing mechanism has been thoroughly demonstrated by ground-state absorption, steady-state emission, and time-resolved emission measurements. The selectivity of the sensor was tested using lysozyme, α-amylase, pepsin, trypsin, lipase, and glucose oxidase in the heparinase selectivity study and the method is also validated using another method reported in the literature. The study provides a new approach for the development of optical methods for the detection of heparinase and oversulfated chondroitin sulfate, which is currently limited.

Thioflavin-T-Incorporated Cerium-ATP Coordination Polymer Nanoparticles: A Promising System for Detection of Uranyl Ion (UO22+) in Aqueous Medium.

Lanthanide-based coordination polymer nanoparticles (Ln-CPNs) are studied for analytical and biomedical sensing, mainly utilizing the luminescent properties of lanthanides. However, the inclusion of fluorescent guest molecules within the nanoparticles can lead to a stimuli-responsive system with modulated photo-physical properties that can be useful for detecting analytes. In this work, we have synthesized cerium(III) coordination polymer nanoparticles using adenosine triphosphate (ATP) molecules as the ligands. The porous polymeric structure enables CPNs for reversible inclusion and release of thioflavin-T (ThT), which is a weakly emissive dye in the free state but becomes highly emissive when incorporated into the Ce-ATP CPNs. Modulation of the photo-physical properties of ThT-incorporated CPNs in response to the radiotoxic and environmentally alarming uranyl ion (UO22+) has been used for its detection in aqueous medium in the range of 0-20 µM by fluorimetry with an LOD of 80 ng mL-1 (0.34 µM) in deionized water without interference from the most commonly occurring metal ions. Furthermore, the sensing platform has been successfully utilized for UO22+ determination in seawater sample without any pre-treatment and adjustment of pH.

Trypsin Detection Strategies: A Review.

Trypsin, a pancreatic serine protease, due to its narrow specificity and selectivity, has been tremendously used in food technology, proteome analysis, modulating soy protein allergenicity, antihypertensive peptide production, as well as, a biomarker in diseases such as pancreatitis, cystic fibrosis etc. Therefore, simple, sensitive and selective biosensors, for trypsin evaluation, are strongly recommended. This review provides, for the first time, an overview of various sensing systems, developed for the detection of trypsin. We have categorized various sensors, developed in the last ten years, according to their signal output as optical (fluorescence, colorimeter, surface plasmon resonance, liquid crystals), electrochemical (photo-electrochemical, nanopore sensors), piezoelectric and enzyme linked immunosorbant assay based sensors. Under each section, further subsections explain, construction of biosensors on the basis of various natural proteins acting as substrate unit and nucleic acids, nanoparticles, inorganic dyes, polymers etc. as participant interacting units. Their working principles and strategies along with salient features, such as, limit of detection, linearity range, time etc. have been critically analyzed to highlight their comparative merits and demerits. The most sensitive biosensors for trypsin detection is a photo-electrochemical anti-trypsin based immunosensor, with a lowest limit of detection 0.02 ng mL-1; linearity 0.10-100 ng mL-1.

Gargling with 7.5% Sodium Bicarbonate Solution for SARS-CoV-2 Viremia Clearance: Our Institutional Clinical Experience.

BACKGROUND: Gargling had been reported to have some roles in the prevention and treatment of respiratory tract infections. The purpose of this study was to assess the ability of regular gargling using 7.5% sodium bicarbonate to eliminate SARS-CoV-2 in the oropharynx and nasopharynx. MATERIALS AND METHODS: This pilot, open-labeled, nonrandomized, parallel single-center study. The effect of 30 seconds, three times per day gargling using 7.5% sodium bicarbonate solution-25 mL on SARS-CoV-2 viral clearance among coronavirus disease-2019 (COVID-19) patients in a dedicated COVID hospital at All India Institute of Medical Sciences, Patna, Bihar, India. We monitored the progress on by days 0, 1, 2, 3, 4, 5, 6, and 7 by observing variables like clinical category, P/F ratio, neutrophil/lymphocyte ratio (NLR) ratio, platelet count, ferritin, lactate dehydrogenase (LDH), CRP, procalcitonin, d-dimer, INR, APTT, and sequential organ function assessment (SOFA) score. We have also done repeat reverse transcription-polymerase chain reaction (RT-PCR) testing on day 5 and day 7. RESULTS: A total of 10 patients (7 males and 3 females) were included in our study after confirmed COVID positivity. The age range was from 30 to 61 years. Based on clinical severity and P/F ratio, 7 patients were included in the milder group as their ratio was more than 200 and the rest 3 patients were included in the moderate group as P/F ratio was less than 200. Two respondents had comorbidities, which were non-Hodgkin's lymphoma and ovarian carcinoma. Viral clearance was achieved at day 7 in 3 of 10 patients. However, the analysis of using 7.5% sodium bicarbonate 25 mL gargle statistically showed nonsignificant p-value for all of our studied variables. However, the PCR results were negative on 24 hours apart, i.e., on day 5 and day 7. CONCLUSIONS: This is only a preliminary study which showed that gargling with 7.5% sodium bicarbonate may not be effective in achieving early SARS-CoV-2 viral clearance among mild COVID-19 patients. However, still larger studies are required to ascertain the benefit of gargling for different stages of COVID-19 patients with keeping in mind the important variables suggestive of viremia clearance. HOW TO CITE THIS ARTICLE: Kumar N, Kumar A, Mahto M, Singh PK. Gargling with 7.5% Sodium Bicarbonate Solution for SARS-CoV-2 Viremia Clearance: Our Institutional Clinical Experience. Indian J Crit Care Med 2021;25(7):791-794.

Off-label Use of Itolizumab in Patients with COVID-19 ARDS: Our Clinical Experience in a Dedicated COVID Center.

Severe acute respiratory syndrome coronavirus 2 has affected millions of people worldwide. This pandemic requires newer medical management strategies to control the morbidity and mortality associated with the disease. Several approaches, including global targeting of inflammation or neutralizing a single key inflammatory mediator, are being employed to cope with cytokine storms in coronavirus disease-2019 (COVID-19). The role of anti-inflammatory biologics, such as acalabrutinib, tocilizumab, anakinra, and itolizumab can become relevant. Itolizumab is a humanized recombinant immunoglobulin G1 monoclonal antibody. It targets the extracellular, scavenger receptor cysteine-rich (SRCR) distal domain 1 of CD6 and is responsible for priming, activation, and differentiation of T-cells. Itolizumab has been approved by the Drug Controller General of India for the treatment of COVID-19 in India. Here, we shared our clinical experience of 20 patients having moderate acute respiratory distress syndrome (ARDS) due to COVID-19 on treatment with itolizumab. We observed the mortality benefit with single-dose itolizumab (1.6 mg/kg) in patients having moderate COVID-19 ARDS. HOW TO CITE THIS ARTICLE: Kumari P, Kumar A, Sinha C, Kumar A, Singh PK, Arun SK. Off-label Use of Itolizumab in Patients with COVID-19 ARDS: Our Clinical Experience in a Dedicated COVID Center. Indian J Crit Care Med 2021;25(4):467-469.

A novel supramolecule-based fluorescence turn-on and ratiometric sensor for highly selective detection of glutathione over cystein and homocystein.

A cyclodextrin-based fluorescence light-up and ratiometric sensor is reported for highly selective and sensitive recognition of glutathione over cystein and homocystein. The sensing scheme developed builds up on a supramolecular assembly formed between a molecular rotor dye (ThT) and a polyanionic supramolecular host (sulfated-ß-cyclodextrin, SCD). The detection scheme is accomplished as follows: firstly, the bivalent Cu2+ quenches the emission from ThT-SCD assembly by causing the dissociation of ThT molecules from SCD surface. Secondly, when GSH is added to the copper-quenched system, owing to specific interaction between Cu2+ and GSH, Cu2+ is removed from the SCD which again allows the formation of ThT-SCD assembly. Indeed, this scheme of disassembly and reassembly successively caused by Cu2+ and GSH in the aqueous solution empowers our sensor framework to work as a good ratiometric sensor for the detection of GSH. The sensor scheme shows a linear response in the range 0-250 µM with a LOD of 2.4 ± 0.2 µM in aqueous solution and 13.6 ± 0.5 µM in diluted human serum sample. The sensor system is excited at 410 nm and the emission signal is plotted as a ratio of intensity at 545 nm (aggregate band) and 490 nm (monomer band). This ratiometric sensor system is highly selective to glutathione over cystein, homocystein, and other amino acids. Additionally, response of the sensor system towards GSH in complex biological media of serum samples demonstrates its potential for practical utility. Graphical abstract.

A supramolecule based fluorescence turn-on and ratiometric sensor for ATP in aqueous solution.

Considering the biological relevance of adenosine triphosphate (ATP) as an "energy currency" in all organisms and significance of its detection in various diseased conditions, enormous efforts have been made to develop selective and sensitive fluorescent sensors for the detection of ATP. However, these developed sensor probes frequently involve technically challenging and time-consuming synthetic protocols for the production of sensor molecules and often suffer from poor solubility in aqueous medium. Another major disadvantage of these developed sensor systems is their single wavelength based operation which makes their performance susceptible to minute changes in experimental conditions. Herein, we report a fluorescence turn-on ratiometric sensor for the detection of ATP which operates by the dissociation of Thioflavin-T-sulphated-ß-cyclodextrin supramolecular assembly by Zn2+ followed by ATP induced reassociation of the same. This modulation of the monomer/aggregate equilibrium of the supramolecular assembly followed by subsequent interactions with Zn2+ and ATP acts as an optimal scheme for the ratiometric detection of ATP. Overall this supramolecular ensemble based sensing platform provides a simple, sensitive, selective and label free detection approach for ATP in aqueous solution. Importantly, our sensor platform responds to ATP in the biologically complex media of serum samples suggesting its potential for possible applications in real-life scenarios.

Acute post-operative diabetic ketoacidosis: Atypical harbinger unmasking latent diabetes mellitus.

Hyperglycaemia following surgical and anaesthetic stress is a well-established entity which might have undesirable clinical consequences in known diabetics. We encountered a rare event where an undiagnosed diabetic patient developed ketoacidosis in the immediate post-operative period which was her initial presenting symptom of deranged glucoregulation. Presumably, the stress induced by surgery and anaesthesia lead to the genesis of this event. We discuss the management of this case. In addition, we highlight the importance of glycosylated haemoglobin as a subject of future research in identifying such "at risk" patients and for stratifying the risk of hyperglycaemic complications in perioperative settings.

An unusual cause of unilateral facial injuries caused by horseshoe headrest during prone positional craniovertebral junction surgery.

Pressure injuries are an accepted complication of prone positioning during the neurosurgical procedures. Horseshoe headrest are intended to reduce the incidence and severity of such injuries by allowing limited areas of contact between the skin of dependent areas of contact and the supporting surfaces. We report a case where a patient positioned prone over a horseshoe headrest developed inadvertent unilateral facial pressure injuries following a 6-h long craniovertebral junction (CVJ) surgery. We attempt to highlight this complication, analyze its causation, and briefly review the existing literature related to similar reported injuries.

Convulsions following rapid ceftazidime administration for preinduction antibiotic prophylaxis during neurosurgical procedure.

Ceftazidime is a widely used antibiotic with broad spectrum activity against Gram-positive and Gram-negative microbes and is used prophylactically in neurosurgical patients prior to surgery. Neurotoxicity is a recognized complication of ceftazidime use but is reported predominantly after repeated administration in patients with impaired renal status. We encountered a patient with an intracranial tumor who developed generalized convulsions following a single dose of ceftazidime, which was infused rapidly and attempt to provide an explanation of this uncommon occurrence.

Effects of preoperative single dose Etoricoxib on postoperative pain and sleep after lumbar diskectomy: prospective randomized double blind controlled study.

BACKGROUND: Etoricoxib, a selective Cox-2 inhibitor has been found to be effective in the management of acute pain. This study evaluates the effect of preoperative use of oral Etoricoxib on post operative pain relief and sleep in patients undergoing single level diskectomy. METHODS: In this prospective, randomized, controlled study, forty four patient (ASA 1 & 2, age 18-60 years) scheduled to undergo single level lumber diskectomy were given either placebo (control group) or Etoricoxib 120 mg orally one hour before surgery. Post operatively fentanyl intravenous (IV) PCA pump was started. Visual analog score (VAS) was assessed at 0, 6, 12, 18 and 24 hours at rest and movement. Primary end point was total pain relief over 24 hours. Sleep overnight, total fentanyl consumption, incidence of nausea and vomiting, intra-operative blood loss and patient satisfaction were noted. RESULTS: Forty three patients completed the study. Reductions in VAS at rest and on movement were observed in the Etoricoxib group when compared with the Control group at all the intervals till 24 hours postoperatively, except on movement at 24 hours postoperative (P < 0.05). Total fentanyl consumption (microg/kg/hr) was higher in Control group (P = 0.007). More patients in Etoricoxib group had a contented facial expression (p = 0.003), relaxed body language (p = 0.00) and better sleep at night than control group (p = 0.0004). CONCLUSION: Single preoperative oral dose (120 mg) of Etoricoxib, given one hour before surgery, has significantly reduced the post operative pain at rest and movement and improved sleep in patients undergoing single level diskectomy without any side effects and with good patient satisfaction.

Comparative evaluation of atenolol and clonidine premedication on cardiovascular response to nasal speculum insertion during trans-sphenoid surgery for resection of pituitary adenoma: A prospective, randomised, double-blind, controlled study.

Severe cardiovascular responses in the form of tachycardia and hypertension following nasal speculum insertion occur during sublabial rhinoseptal trans-sphenoid approach for resection of small pituitary tumours. We compare the effects of preoperative administration of clonidine (α-2 agonist) and atenolol (α-blocker) over haemodynamic response, caused by speculum insertion during trans-sphenoid pituitary resection. We enrolled 66 patients in age range 18-65 years, of ASA I-II, and of either sex undergoing elective sublabial rhinoseptal trans-sphenoidal hypophysectomy. Group I (control) received placebo, group II (clonidine) received tablet clonidine 5 µg/kg, and group III (atenolol) received tablet atenolol 0.5 mg/kg. The heart rate increased on speculum insertion and 5 and 10 minutes following speculum insertion as compared to the pre-speculum values in the control group, while no change in the heart rate was observed in other groups (P<0.05). There was a rise in the mean arterial pressure during and 5, 10, and 15 minutes after nasal speculum insertion in the control group, whereas it was not seen in other groups (P<0.05). We therefore suggest that oral clonidine and oral atenolol (given 2 hours prior to surgery) is an equally effective and safe method of attenuating haemodynamic response caused by nasal speculum insertion during trans-sphenoid pituitary resection.

The response of the vascular beds to sodium bicarbonate in patients during normothermic bypass.

OBJECTIVES: Cardiopulmonary bypass (CPB) provides a unique circumstance to study the effects of drugs on the systemic vasculature. Thus, this study was designed to evaluate the effects of sodium bicarbonate on the systemic circulation during CPB in humans. DESIGN: Randomized, double-blind study. SETTING: Tertiary care university hospital. PARTICIPANTS: Patients presenting for coronary artery bypass graft surgery with CPB. INTERVENTIONS: In this double-blind study, 22 consecutive adult patients of both sexes undergoing cardiac surgery were randomized into 2 groups. After establishing CPB and cardioplegia, patients in group 1 (n = 11) received saline (0.9%) (1.2 mL/kg), and group 2 received sodium bicarbonate (SB) (7%) (1.2 mL/kg). The blood level in the cardiotomy reservoir, pump flow, and mean arterial pressure were measured for 25 minutes. MEASUREMENTS AND MAIN RESULTS: The SB-treated patients (group 2) showed significantly greater (p < 0.05) decreases in cardiotomy reservoir blood volume (336 +/- 186 mL) than the saline-treated (140 +/- 97 mL) patients. The mean arterial pressure in group 2 patients significantly (p < 0.05) increased (from 49 +/- 11.9 to 65 +/- 5.3 mmHg) more than in the saline group (from 50 +/- 6.8 to 57 +/- 9.2 mmHg) after 20 minutes. The decrease in reservoir volume significantly (p < 0.05) and inversely correlated (r = -0.61) with the acidotic state of the patients before SB. CONCLUSIONS: This study found a biphasic response to SB on the systemic circulation during CPB. Early dilation of venous capacitance vessels occurred followed by arteriolar constriction over the 20-minute study interval.