Recent advances in research, training and teaching in anaesthesia and critical care.

Teaching and learning in anaesthesia and critical care has traditionally included seminars, journal clubs and clinical teaching in the operation theatre. The aim has always been to ignite the spark of thinking and self-directed learning in the students. The process of 'dissertation preparation' introduces basic knowledge and interest in research in the postgraduate student. All this is followed by an examination at the end of the course including the theory and practical assessment in the form of long and short case discussions and table viva-voce. The National Medical Commission in 2019 introduced the competency-based medical education curriculum for anaesthesia postgraduates. This curriculum focuses on structured teaching and learning. It has specific learning objectives in theoretical knowledge, skills and attitude development. The building up of communication skills has been given due importance. Though research in anaesthesia and critical care is steadily progressing, much work needs to be done on its improvement.

Comparative Evaluation of the Intravenous Dexmedetomidine and Nalbuphine for Treatment of Post Spinal Shivering-A Randomized Prospective Trial.

BACKGROUND: Shivering is one of the most common complications of spinal anesthesia because of inhibition of the thermoregulatory control. Dexmedetomidine and nalbuphine are the two commonly used drugs for treatment of perioperative shivering, but owing to paucity of their comparative data, we planned this study to compare the efficacy of these two drugs for treatment of post spinal shivering. METHODS: This study was conducted on 80 American Society of Anesthesiologists physical status I or II patients aged from 18 to 60 years who developed post-spinal shivering of grade III or IV during elective surgeries. These patients were randomly allocated into two groups (40 each). In group D, dexmedetomidine 0.50 µg/kg, and in group N, nalbuphine 0.08 mg/kg was given intravenously for treatment of shivering. Data regarding response time, recurrence rate and success rate along with their adverse effects were noted, and statistical analysis was performed using SPSS software version 17.0 (SPSS Inc., Chicago, IL, USA). RESULTS: The mean response time was significantly shorter in group D as compared to Group N (1.9 ± 0.6 min and 4.7 ± 1.1 min, respectively; P ＜ 0.001), but the success rate in both groups was 100%. Recurrence of shivering was greater in group N as compared to group D, but this difference was statistically insignificant. Although hypotension and bradycardia were observed more in group D and nausea was observed more in group N, the difference among both the groups was statistically insignificant. CONCLUSIONS: Dexmedetomidine is a better alternative than nalbuphine for treatment of post spinal shivering with quicker response time and comparable side effects.

Comparative evaluation of propofol versus dexmedetomidine infusion for hypotensive anesthesia during functional endoscopic sinus surgery: a prospective randomized trial.

BACKGROUND: During functional endoscopic sinus surgery (FESS), intranasal bleeding affects operative field visibility and increases the frequency of complications. Therefore, hypotensive anesthesia is a widely used technique to improve surgical outcomes. This study aimed to compare the efficacy of propofol and dexmedetomidine infusion for hypotensive anesthesia in patients undergoing FESS. METHODS: This prospective randomized trial was conducted in 80 adult patients who were scheduled for FESS under general anesthesia. Patients were randomly divided into two groups: group P (n = 40) received propofol infusion of 100-200 µg/kg/min and group D (n = 40) received dexmedetomidine infusion with a loading dose of 1 µg/kg over 10 min after induction, followed by maintenance infusion of 0.4-0.8 µg/kg/h. Intraoperative blood loss, quality of the surgical field (Fromme- Boezaart scale), hemodynamic control, and patient recovery were recorded. Statistical analysis was performed using Student's t-test, chi-square test, and Mann-Whitney U test. RESULTS: The mean arterial pressure and heart rate were significantly lower in group D throughout the surgery than in group P. Blood loss was significantly higher in group P (100.73 ± 18.12 ml) than in group D (85.70 ± 18.56 ml). The average number of patients with Fromme's score 1/2/3 was comparable between the groups. Intraoperatively, only one incidence of bradycardia and hypotension was observed in group D (2.5%) compared to group P. CONCLUSIONS: Both dexmedetomidine and propofol are efficacious and safe drugs for facilitating controlled hypotension during FESS; however, dexmedetomidine provides better hemodynamic control and is associated with lesser blood loss without any significant adverse effects.

Vegetative Insecticidal Protein (Vip): A Potential Contender From Bacillus thuringiensis for Efficient Management of Various Detrimental Agricultural Pests.

Bacillus thuringiensis (Bt) bacterium is found in various ecological habitats, and has natural entomo-pesticidal properties, due to the production of crystalline and soluble proteins during different growth phases. In addition to Cry and Cyt proteins, this bacterium also produces Vegetative insecticidal protein (Vip) during its vegetative growth phase, which is considered an excellent toxic candidate because of the difference in sequence homology and receptor sites from Cry proteins. Vip proteins are referred as second-generation insecticidal proteins, which can be used either alone or in complementarity with Cry proteins for the management of various detrimental pests. Among these Vip proteins, Vip1 and Vip2 act as binary toxins and have toxicity toward pests belonging to Hemiptera and Coleoptera orders, whereas the most important Vip3 proteins have insecticidal activity against Lepidopteran pests. These Vip3 proteins are similar to Cry proteins in terms of toxicity potential against susceptible insects. They are reported to be toxic toward pests, which can't be controlled with Cry proteins. The Vip3 proteins have been successfully pyramided along with Cry proteins in transgenic rice, corn, and cotton to combat resistant pest populations. This review provides detailed information about the history and importance of Vip proteins, their types, structure, newly identified specific receptors, and action mechanism of this specific class of proteins. Various studies conducted on Vip proteins all over the world and the current status have been discussed. This review will give insights into the significance of Vip proteins as alternative promising candidate toxic proteins from Bt for the management of pests in most sustainable manner.

Hemodynamic Response to Orotracheal Intubation: Comparison between Macintosh, McCoy, and C-MAC Video Laryngoscope.

BACKGROUND: The most commonly used devices for direct visualization of the larynx and tracheal intubation are Macintosh and McCoy laryngoscopes. C-MAC video laryngoscope, based on the principles of indirect laryngoscopy, has been introduced into clinical practice in recent years. Video laryngoscope may be useful in difficult tracheal intubation situations. AIM: We aimed at comparing the McCoy and C-MAC video laryngoscope with conventional Macintosh laryngoscope for hemodynamic responses of orotracheal intubation among adults receiving general anesthesia for elective surgeries. SETTINGS AND DESIGN: This was a hospital-based randomized, double-blind, comparison, done between June 2015 and October 2016 after permission of institutional ethical committee. MATERIALS AND METHODS: One hundred and fifty patients with normal airways undergoing elective general anesthesia were randomly allocated to undergo intubation using either Macintosh (Group A), McCoy (Group B), or C-MAC video laryngoscope (Group C). Hemodynamic changes associated with intubation were recorded immediately before and after laryngoscopy and intubation, every minute for 5 min and at 10 min after intubation by an independent observer. The time taken to perform endotracheal intubation and Cormack and Lehane score were also noted in all three groups. STATISTICAL ANALYSIS: Data were compiled, and statistical analysis was performed using SPSS 17.0 version. RESULTS: Hemodynamic response after intubation was least in Group B (McCoy) as compared to Group A (Macintosh) and Group C (C-Mac) (P = 0.001). Ninety-two percentage patients were in Cormack and Lehane score Class I in Group C in comparison to 52% in Group A and 48% in Group B (P = 0.000). Time for intubation taken in Group A, Group B, and Group C was 15.53 ± 1.53 min, 18.65 ± 0.44 min, and 22.82 ± 1.323 min, respectively (P = 0.000). CONCLUSION: The McCoy laryngoscope provided better attenuation of hemodynamic responses to laryngoscopy and intubation than the Macintosh and C-Mac video laryngoscope whereas more appearance of Cormack and Lehane score Class I was seen with the C-MAC video laryngoscope. Furthermore, the time taken to perform endotracheal intubation was the longest with the C-MAC video laryngoscope.

Structural characterization and heterologous expression of a new cyt gene cloned from Bacillus thuringiensis.

Bacillus thuringiensis (Bt) strains produce Cry (crystal) and Cyt (cytolytic) proteins belonging to the group of bacterial toxins known as pore-forming toxins (PFTs), which interact with midgut cells of target insects to create pores, disruption of ion homeostasis and eventual death. PFTs have synergistic insecticidal activities and have been used as biopesticides against agriculturally important insects. Identification of new Cyt proteins is important because of their specific toxicity towards hemipteran pests, against which the Cry proteins are not effective. We have structurally characterized a cyt (cyt1007) gene from an Indian Bt isolate SK-1007. The presence of a "Bacillus thuringiensis toxin" domain and maximum identity of 36% with Cyt2Ca in the deduced amino acid sequence indicated Cyt1007 protein to be a new member of Cyt family. Three dimensional (3D) modeling (PMDB ID: PM0081490) revealed that it adopts a typical ferredoxin-like fold, and is composed of a single domain of α/ß architecture, in which a single ß sheet is surrounded by two α helical layers. The putative lipid binding site and probable mode of action of Cyt1007 protein were predicted through comparative analysis with other Cyt toxins and their distant homologs Evf (Erwinia virulence factor) and VVA2 (Volvatoxin A2). Heterologous expression of cyt1007 gene as a 25 kDa protein in Escherichia coli was achieved at high levels in both soluble and insoluble fractions. Affinity chromatography-based purification yielded 83.6% purified Cyt1007 protein, which can be used for downstream applications for the investigation of its toxicity. Graphical abstract Steps in the structural characterization and heterologous expression of a new cyt gene cloned from Bacillus thuringiensis.

A novel cry52Ca1 gene from an Indian Bacillus thuringiensis isolate is toxic to Helicoverpa armigera (cotton boll worm).

The novel cry52Ca1 gene from an Indian Bacillus thuringiensis (Bt) isolate was cloned in an expression vector (pET301/CT-DEST, 6xHis). The gene expressed as a ∼77.2 kDa protein in E. coli BL21-CodonPlus (DE3)-RIPL cells upon induction with isopropyl-thio-galactoside (IPTG) for 18 h at 28 °C. Cry52Ca1 protein was toxic to Helicoverpa armigera (cotton bollworm) neonate larvae (LC50 36.66 µg per ml and MIC50 3.051 µg per ml) in diet-based laboratory assays. This gene has potential for deployment in insect-resistant transgenic crops.

A Study to Compare the Analgesic Efficacy of Dexmedetomidine and Fentanyl as Adjuvants to Levobupivacaine in Ultrasound-Guided Supraclavicular Brachial Plexus Block.

BACKGROUND: Supraclavicular brachial plexus provides complete and reliable anesthesia for upper limb surgeries. Adjuvants are added to local anesthetists to improve various block characteristics. There are limited studies comparing the efficacy of dexmedetomidine and fentanyl as an adjuvant to levobupivacaine. AIMS: The aim of the study was to evaluate and compare the effect of dexmedetomidine versus fentanyl as an adjuvant with levobupivacaine in ultrasound-guided supraclavicular brachial plexus block. SETTINGS AND DESIGN: This study design was a prospective, randomized, double-blind controlled study. SUBJECTS AND METHODS: A total of 120 patients in the age group of 30-55 years with physical status American Society of Anesthesiologists Classes I and II undergoing elective upper limb surgeries under ultrasound-guided supraclavicular brachial plexus block were randomly divided into three groups of forty each after taking informed consent and approval from Hospital Ethics Committee: Group A received 25 ml of 0.5% levobupivacaine with 5 ml normal saline (NS). Group B received 25 ml of 0.5% levobupivacaine with 1 µg/kg dexmedetomidine diluted to the volume of 5 ml NS. Group C received 25 ml of 0.5% levobupivacaine with 1 µg/kg fentanyl diluted to the volume of 5 ml NS. Onset and duration of sensory and motor block and duration of analgesia were noted and any side effects were observed. STATISTICAL ANALYSIS: The distribution of variables tested with Shapiro-Wilk test. Group comparison of values was made by Kruskal-Wallis test followed by Mann-Whitney test. RESULTS: There was fastest onset time as well as longer duration of sensory and motor block in dexmedetomidine group, intermediate in fentanyl group as compared to levobupivacaine group. CONCLUSION: This study concludes that addition of dexmedetomidine to levobupivacaine for supraclavicular brachial plexus block shortens the onset time and prolongs the duration of sensory and motor blockade as compared to the addition of fentanyl.

Pool deconvolution approach for high-throughput gene mining from Bacillus thuringiensis.

Novel genes from Bacillus thuringiensis (Bt) are required for effective deployment in agriculture, human health, and forestry. In an improvement over conventional PCR-based screening, next generation sequencing (NGS) has been used for identification of new genes of potential interest from Bt strains, but cost becomes a constraint when several isolates are to be sequenced. We demonstrate the potential of a DNA pooling strategy known as pool deconvolution to identify commercially important toxin genes from 36 native Bt isolates. This strategy is divided into three steps: (a) DNA pooling, (b) short read sequence assembly followed by gene mining, and (c) host isolate identification. With this approach, we have identified insecticidal protein (ip) genes including nine three-domain (3D) cry genes, three cyt-type genes, three mtx genes (mosquitocidal toxin), and one bin and vip-type gene each. Three cry-type and three cyt-type genes were cloned, out of which, two cry-type genes, ip11 and ip13, were named as cry4Ca2 and cry52Ca1, respectively by the Bacillus thuringiensis nomenclature committee ( http://www.biols.susx.ac.uk/Home/Neil_Crickmore/BT/ ). Our results show that the pool deconvolution approach is well suited for high-throughput gene mining in bacteria.

Prevalence of cry2-type genes in Bacillus thuringiensis isolates recovered from diverse habitats in India and isolation of a novel cry2Af2 gene toxic to Helicoverpa armigera (cotton boll worm).

Insecticidal cry and vip genes from Bacillus thuringiensis (Bt) have been used for control of lepidopteran insects in transgenic crops. However, novel genes are required for gene pyramiding to delay evolution of resistance to the currently deployed genes. Two PCR-based techniques were employed for screening of cry2-type genes in 129 Bt isolates from diverse habitats in India and 27 known Bt strains. cry2Ab-type genes were more prevalent than cry2Aa- and cry2Ac-type genes. Correlation between source of isolates and abundance of cry2-type genes was not observed. Full-length cry2A-type genes were amplified by PCR from 9 Bt isolates and 4 Bt strains. The genes from Bt isolates SK-758 from Sorghum grain dust and SK-793 from Chilli seeds warehouse, Andhra Pradesh, were cloned and sequenced. The gene from SK-758 (NCBI GenBank accession No. GQ866915) was novel, while that from SK-793 (NCBI GenBank accession No. GQ866914) was identical to the cry2Ab1 gene. The Bacillus thuringiensis Nomenclature Committee ( http://www.lifesci.sussex.ac.uk/home/Neil_Crickmore/Bt/toxins2.html ) named these genes cry2Af2 and cry2Ab16, respectively. The cry2Af2 gene was expressed in Escherichia coli and found to be toxic towards Helicoverpa armigera. The cry2Af2 gene will be useful for pyramiding in transgenic crops.

Arousal from sedation in lower abdominal surgeries under spinal anesthesia: Comparison between dexmedetomidine and clonidine.

BACKGROUND AND AIM: Dexmedetomidine and clonidine are commonly used drugs for sedation during regional anesthesia. However, data regarding arousal time from sedation with these drugs is sparse. Hence, we designed a study to compare arousal time from sedation with dexmedetomidine and clonidine during spinal anesthesia. We also tried to find out the correlation between clinical and objective method used for assessing the depth of sedation. MATERIALS AND METHODS: In this study, 120 patients were randomly assigned in two groups to receive either dexmedetomidine (Group DE, n = 60) or Clonidine (Group CL, n = 60). Group DE received 1 µg/kg of dexmedetomidine followed by infusion at 0.5 µg/kg/h while Group CL received 1 µg/kg of clonidine followed by infusion at 1 µg/kg/h and titration until targeted Ramsay sedation scale (RSS) score of 3-5 was achieved and maintained. RSS and bispectral (BIS) were monitored until arousal of the patients. The time to achieve RSS of 2 and BIS of 90 during recovery, the correlation between BIS and RSS score in both the study groups and duration of postoperative analgesia were noted. STATISTICAL ANALYSIS USED: Chi-square tests for nonparametric data and Student's t-test for parametric data were used. Correlation between RSS and BIS was calculated with spearman correlation method. RESULTS: Arousal time from sedation and time to reach BIS score 90 was lower for Group DE as compared to Group CL (P = 0.001). Dexmedetomidine also increased the time to first postoperative analgesic request when compared with clonidine (198.23 ± 33.15 min vs. 150.65 ± 28.55 min, P = 0.01). CONCLUSIONS: Intravenous dexmedetomidine infusion has shorter arousal time from sedation than clonidine during spinal anesthesia. A strong correlation exists between BIS and RSS during recovery from sedation.

Effect of intraoperative infusion of low-dose ketamine on management of postoperative analgesia.

BACKGROUND: Use of opioids for perioperative analgesia is associated with sedation, respiratory depression and postoperative nausea and vomiting. N-methyl-D-aspartate receptor antagonist such as ketamine has both analgesic and antihyperalgesic properties. We studied the effect of intraoperative infusion of low-dose ketamine on postoperative analgesia and its management with opioids. MATERIALS AND METHODS: A total of 80 patients scheduled for open cholecystectomy under general anesthesia were randomly allocated into two equal groups in a randomized double-blinded way. The general anesthetic technique was standardized in both groups. Group K patients (n = 40) received bolus of ketamine 0.2 mg/kg intravenously followed by an infusion of 0.1 mg/kg/h before skin incision, which was continued up to the end of surgery. Similar volume of saline was infused in Group C (n = 40). The pain score at different intervals and cumulative morphine consumption over 24 h was observed. Secondary outcomes such as hemodynamic parameters, patient satisfaction score and incidences of side effects were also recorded. RESULTS: Intraoperative infusion of low-dose ketamine resulted in effective analgesia in first 6 h of the postoperative period, which was evident from reduced pain scores and reduced opioid requirements (P = 0.001). The incidence of side effects and patient satisfaction were similar in both groups. CONCLUSION: Intraoperative low-dose ketamine infusion provides good postoperative analgesia while reducing need of opioid analgesics, which must be considered for better management of postoperative analgesia.

Molecular typing of native Bacillus thuringiensis isolates from diverse habitats in India using REP-PCR and ERIC-PCR analysis.

Bacillus thuringiensis is a bacterium of great agronomic and scientific interest. The subspecies of this bacterium colonize and kill a large variety of host insects and even nematodes, but each strain does so with a high degree of specificity. Therefore molecular typing and diversity analysis of B. thuringiensis has enormous importance for discrimination of strains isolated from different sources. In this study, 113 native B. thuringiensis isolates collected from diverse habitats and locations in India and 27 B. thuringiensis type strains obtained from the Bacillus Genetic Stock Centre (BGSC), Ohio State University, USA and used as reference, were analyzed for molecular typing. Genotypic data of 140 B. thuringiensis isolates and type strains was generated by using REP-PCR and ERIC-PCR primers and unweighted pair group method with arithmetic mean (UPGMA) analysis using NTSYSpc2.2 and grouped into 4 main clusters. All the groups have isolates from diverse origins. No group was found to represent any specific origin or location. The observed patterns of REP-PCR and ERIC-PCR pattern were discriminatory enough to reveal differences in the B. thuringiensis isolates and reference strains. The resolution power and marker index of the ERIC-PCR (RP 9.39, MI 6.34) was found to be higher than that of the REP-PCR (RP 6.20, MI 4.48). The REP-PCR and ERIC-PCR markers have been found to be useful for discrimination of B. thuringiensis isolates and reference strains. ERIC-PCR was the more informative of the two techniques. This study showed that the B. thuringiensis isolates collected from diverse habitats in India had a high degree of genetic diversity.