Total Synthesis of a PSGL-1 Glycopeptide Analogue for Targeted Inhibition of P-Selectin.

The high affinity interaction between P-selectin glycoprotein ligand-1 (PSGL-1) and P-selectin is mediated by a multimotif glycosulfopeptide (GSP) recognition domain consisting of clustered tyrosine sulfates and a Core 2 O-glycan terminated with sialyl LewisX (C2-O-sLeX). These distinct GSP motifs are much more common than previously appreciated within a wide variety of functionally important domains involved in protein-protein interactions. However, despite the potential of GSPs to serve as tools for fundamental studies and prospects for drug discovery, their utility has been limited by the absence of chemical schemes for synthesis on scale. Herein, we report the total synthesis of GSnP-6, an analogue of the N-terminal domain of PSGL-1, and potent inhibitor of P-selectin. An efficient, scalable, hydrogenolysis-free synthesis of C2-O-sLeX-Thr-COOH was identified by both convergent and orthogonal one-pot assembly, which afforded this crucial building block, ready for direct use in solid phase peptide synthesis (SPPS). C2-O-sLeX-Thr-COOH was synthesized in 10 steps with an overall yield of 23% from the 4-O,5-N oxazolidinone thiosialoside donor. This synthesis represents an 80-fold improvement in reaction yield as compared to prior reports, achieving the first gram scale synthesis of SPPS ready C2-O-sLeX-Thr-COOH and enabling the scalable synthesis of GSnP-6 for preclinical evaluation. Significantly, we established that GSnP-6 displays dose-dependent inhibition of venous thrombosis in vivo and inhibits vaso-occlusive events in a human sickle cell disease equivalent microvasculature-on-a-chip system. The insights gained in formulating this design strategy can be broadly applied to the synthesis of a wide variety of biologically important oligosaccharides and O-glycan bearing glycopeptides.

Study of Biochemical Parameters as Predictors for Need of Invasive Ventilation in Severely Ill COVID-19 Patients.

Background: Though laboratory tests have been shown to predict mortality in COVID-19, there is still a dearth of information regarding the role of biochemical parameters in predicting the type of ventilatory support that these patients may require. Methods: The purpose of our retrospective observational study was to investigate the relationship between biochemical parameters and the type of ventilatory support needed for the intensive care of severely ill COVID-19 patients. We comprehensively recorded history, physical examination, vital signs from point-of-care testing (POCT) devices, clinical diagnosis, details of the ventilatory support required in intensive care and the results of the biochemical analysis at the time of admission. Appropriate statistical methods were used and P-values < 0.05 were considered significant. Receiver operating characteristics (ROC) analysis was performed and Area Under the Curve (AUC) of 0.6 to 0.7, 0.7 to 0.8, 0.8 to 0.9, and >0.9, respectively, were regarded as acceptable, fair, good, and exceptional for discrimination. Results: Statistically significant differences (p<0.05) in Urea (p = 0.0351), Sodium (p = 0.0142), Indirect Bilirubin (p = 0.0251), Albumin (p = 0.0272), Aspartate Transaminase (AST) (p = 0.0060) and Procalcitonin (PCT) (p = 0.0420) were observed between the patients who were maintained on non-invasive ventilations as compared to those who required invasive ventilation. In patients who required invasive ventilation, the levels of Urea, Sodium, Indirect bilirubin, AST and PCT were higher while Albumin was lower. On ROC analysis, higher levels of Albumin was found to be acceptable indicator of maintenance on non-invasive ventilation while higher levels of Sodium and PCT were found to be fair predictor of requirement of invasive ventilation. Conclusion: Our study emphasizes the role of biochemical parameters in predicting the type of ventilatory support that is needed in order to properly manage severely ill COVID-19 patients.

Biochemical Parameters as Prognostic Markers in Severely Ill COVID-19 Patients.

Background Prognostication plays a pivotal role in critical care medicine. Its importance is indisputable in the management of coronavirus disease 2019 (COVID-19), as the presentation of this disease may vary from docile, self-limiting symptoms to lethal conditions. Amid the COVID-19 pandemic, much emphasis was initially placed on molecular and serological testing. However, it was realized later that routine laboratory tests also provide key information in terms of the severity of the disease and thus could be used to predict the outcome of these patients. Methodology The aim of our study was to evaluate the biochemical parameters as prognostic markers in severely ill COVID-19 patients. We carried out a retrospective, case-control study. The study population was comprised of all severely ill COVID-19 patients admitted between October 2020 and January 2021 at our level 3 COVID hospital. Cases were defined as the patients who expired despite treatment and all resuscitative measures as per the standard operating procedures (SOPs) of our COVID intensive care unit (ICU) while controls were defined as the patients that were transferred out of the COVID ICU for further recovery. The detailed history, findings of physical examination, vitals recorded by point of care testing (POCT) devices at our ICU, clinical diagnosis, and the results of the biochemical analysis were recorded in a specially designed pro forma. The biochemical parameters recorded at the time of admission were compared between the groups of controls and cases in order to evaluate their role as predictors of mortality using appropriate statistical methods. P-values less than 0.05 were considered statistically significant. For all the parameters that showed a statistically significant difference, receiver operating characteristics (ROC) analysis was done to assess the utility of biochemical parameters as predictors of mortality or survival. Areas under the curve (AUCs) of 0.6 to 0.7, 0.7 to 0.8, 0.8 to 0.9, and >0.9 were considered acceptable, fair, good, and excellent for discrimination, respectively. Results Of the 178 severely ill COVID-19 patients enrolled in the study, 86 were controls and 92 were cases (52% mortality). Serum urea (p<0.0001), creatinine (p=0.0019), aspartate transaminase (AST) (p=0.0104), lactate dehydrogenase (LDH) (p=0.0001), procalcitonin (PCT) (p=0.0344), and interleukin 6 (IL-6) (p=0.0311) levels were significantly higher (p<0.05), while total protein (p=0.0086), albumin (p<0.0001), and indirect bilirubin (p=0.0147) levels were significantly lower (p<0.05) in cases as compared to controls. The difference was statistically insignificant (p>0.05) for serum sodium, potassium, total and direct bilirubin, globulin, alanine transaminase (ALT), alkaline phosphatase (ALP), D-dimer, and ferritin. On ROC analysis, urea was fair (AUC=0.721), creatinine (AUC=0.698) and IL-6 (AUC=0.698) were acceptable predictors of mortality, while albumin (AUC=0.698) was an acceptable predictor of survival in severely ill COVID-19 patients during their intensive care stay. Conclusion Understanding the pathophysiological changes associated with the severity of COVID-19 in terms of an alteration of biochemical parameters is a pressing priority. Our study highlights the importance of routine laboratory tests in predicting outcomes in severely ill COVID-19 patients.

Sequential Combined Spinal-epidural Anesthesia in a Multiple Comorbidity Patient: An Indispensable Tool in Anesthesiologists' Armamentarium.

Primary total knee joint arthroplasty (TKA) is a frequently performed procedure as part of osteoarthritis treatment. Optimal perioperative analgesia will augment functional recovery, improve knee mobility, and reduce postoperative morbidity. Octa- and nonagenarians undergoing TKA are often considered particularly difficult to manage and involve high levels of competence due to associated comorbidities these patients present with. We report a case of a geriatric patient with coronary artery disease and low ejection fraction with pulmonary fibrosis who underwent successful total knee arthroplasty under sequential combined spinal-epidural anesthesia.

Comparison of Ultrasound-Guided Transversus Abdominis Plane Block with Sub-Arachnoid Block for Open Inguinal Hernia Repair.

Background: Open inguinal hernia repair is one of the routine day-care procedures performed across the world. A multitude of anesthetic techniques have been outlined for painless inguinal hernia repair, comprising general anesthesia and regional anesthesia such as spinal, epidural, and nerve blocks; with regional anesthetic techniques often favored for uncomplicated open inguinal hernia repair. Ultrasound-guided peripheral nerve blocks have made rapid strides and are gaining popularity because of the reduced incidence of adverse events. Aims: We aim to compare the efficacy of two regional anesthesia techniques to compare the adequacy of surgical anesthesia and their efficacy to ease postoperative pain with least potential side effects. Settings and Design: This prospective, interventional, single-centric, double-blind, randomized, parallel-group, active-controlled, Helsinki protocol-compliant clinical study was registered with the Clinical Trial Registry of India (CTRI/2021/04/033109). It was conducted after obtaining written informed consent from all patients and approval from the institutional review board. Materials and Methods: Sixty patients of American Society of Anesthesiologists physical status classes I/II, in the age group of 18-60 years of either sex, scheduled for elective open inguinal hernia repair, were enrolled into two groups of 30 patients each according to the anesthetic technique used. Group T comprised patients receiving ultrasound-guided transversus abdominis plane block (TAP block), whereas the Group S comprised patients administered spinal anesthesia for elective open inguinal hernia repair. The primary end points of this study were to assess the adequacy of surgical anesthesia and duration of postoperative analgesia, whereas the secondary end points included assessment of patients' hemodynamic profile post institution of the block and comparing the incidence of adverse events associated with the two techniques. Statistical Analysis: SPSS version 20.0 was used for analysis. Frequency, mean distribution, standard deviation, Chi Square test and student t Test were calculated to p value. P < 0.05 was considered statistically significant. Continuous variables were expressed as mean + SD, whereas categorical variables were expressed as absolute numbers and percentages. Intergroup nominal categorical data were compared by Chi-square test. Results: The visual analog scale score was found significantly lower in Group T at all time points except immediate postsurgery (3, 6, 12, 24, and 48 h) as compared to Group S (0.357 ± 0.4880 vs. 1.393 ± 1.8527; P = 0.006, 1.393 ± 0.4973 vs. 2.893 ± 2.3148; P = 0.001, 2.429 ± 0.9201 vs. 3.321 ± 2.0377; P = 0.039, 1.214 ± 0.4179 vs. 2.286 ± 1.9217; P = 0.006, and 1.143 ± 0.3563 vs. 1.643 ± 1.5685; P = 0.106, respectively), and the duration of postoperative analgesia was highly significant (P < 0.001) in Group T (724.00 ± 103.2914 min) as compared to Group S (256.643 ± 73.4218 min). Difference in the number of rescue analgesics administered over the first 24 and 24-48 h was significantly higher in the spinal group which comprised patients administered with the TAP block. Conclusion: Ultrasound-guided TAP block provides better intra-operative and postoperative analgesia as compared to subarachnoid block especially in respiratory and cardiovascular cripples without any significant adverse events and hemodynamic changes.

An expeditious synthesis of blood-group antigens, ABO histo-blood group type II antigens and xenoantigen oligosaccharides with amino type spacer-arms.

Blood group oligosaccharides are one of the most clinically important antigen families and they may also act as secondary ligands for bacterial toxins from Escherichia coli and Vibrio cholerae. Herein we report the synthesis of spacered (sp = CH2CH2CH2NH2) glycosides of A antigen {α-D-GalNAc-(l→3)-[α-L-Fuc-(l→2)]-ß-D-Gal-}, B antigen{α-D-Gal-(l→3)-[α-L-Fuc-(l→2)]-ß-D-Gal-}, LewisX{α-D-Gal-(l→4)-[α-L-Fuc-(l→3)]-ß-D-GlcNAc-}, A type-II {α-D-GalNAc-(l→3)-[α-L-Fuc-(l→2)]-ß-D-Gal-(1→4)-ß-D-GlcNAc-}, B type-II {α-D-Gal-(l→3)-[α-L-Fuc-(l→2)]-ß-D-Gal-(1→4)-ß-D-GlcNAc-}, H type-II{α-L-Fuc-(l→2)-ß-D-Gal-(1→4)-ß-D-GlcNAc-}, xenoantigen {α-D-Gal-(l→3)-ß-D-Gal-(1→4)-[α-L-Fuc-(l→2)]-ß-D-GlcNAc-} and Linear B Type II {α-D-Gal-(l→3)-ß-D-Gal-(1→4)-ß-D-GlcNAc-} useful for a range of biochemical investigations. This linker was chosen so as to facilitate the future conjugation of the antigens to proteins or other molecules. We also measured the affinities of some synthesized oligosaccharides against El Tor CTB strain from V. cholera.