Structure, dynamics, and molecular inhibition of the Staphylococcus aureus m1A22-tRNA methyltransferase TrmK.

The enzyme m1A22-tRNA methyltransferase (TrmK) catalyzes the transfer of a methyl group to the N1 of adenine 22 in bacterial tRNAs. TrmK is essential for Staphylococcus aureus survival during infection but has no homolog in mammals, making it a promising target for antibiotic development. Here, we characterize the structure and function of S. aureus TrmK (SaTrmK) using X-ray crystallography, binding assays, and molecular dynamics simulations. We report crystal structures for the SaTrmK apoenzyme as well as in complexes with methyl donor SAM and co-product product SAH. Isothermal titration calorimetry showed that SAM binds to the enzyme with favorable but modest enthalpic and entropic contributions, whereas SAH binding leads to an entropic penalty compensated for by a large favorable enthalpic contribution. Molecular dynamics simulations point to specific motions of the C-terminal domain being altered by SAM binding, which might have implications for tRNA recruitment. In addition, activity assays for SaTrmK-catalyzed methylation of A22 mutants of tRNALeu demonstrate that the adenine at position 22 is absolutely essential. In silico screening of compounds suggested the multifunctional organic toxin plumbagin as a potential inhibitor of TrmK, which was confirmed by activity measurements. Furthermore, LC-MS data indicated the protein was covalently modified by one equivalent of the inhibitor, and proteolytic digestion coupled with LC-MS identified Cys92 in the vicinity of the SAM-binding site as the sole residue modified. These results identify a cryptic binding pocket of SaTrmK, laying a foundation for future structure-based drug discovery.

Rate and anchorage loss during en-masse retraction between friction and frictionless mechanics: A randomized clinical trial.

OBJECTIVE: To compare rate and anchorage loss during en-masse retraction of anterior maxillary teeth between friction mechanics (FM) and frictionless mechanics (FLM). SETTING AND SAMPLE POPULATION: Thirty-eight patients requiring en-masse retraction of protruded anterior maxillary teeth were randomly allocated into FM and FLM groups. METHODS: En-masse retraction with sliding mechanics (FM) using an elastomeric chain was compared with continuous mushroom loop archwire mechanics (FLM). Study models and lateral cephalograms were taken before (T1) and immediately after retraction (T2). The primary outcome was the rate of en-masse retraction. Anchorage loss was the secondary outcome. Intergroup comparison was performed using an independent t test (P < .05). RESULTS: Baseline characteristics were similar between groups. Thirty-six patients completed the trial. Two patients were lost to follow-up in the FLM group. The rate of en-masse retraction did not differ significantly (P = .625) between FM (0.7 mm/mo) and FLM (0.8 mm/mo) groups. The intragroup comparison showed significant anchorage loss in FM (2.28 mm) and FLM (1.13 mm) groups; however, the intergroup comparison showed no statistically significant difference (P = .093). Maxillary first molar showed a statistically significant change in angulation between the two mechanic groups (P < .001). Vertical movement of the maxillary incisor and first molar showed no significant difference between FM and FLM groups (P = .143, P = .546, respectively). CONCLUSIONS: The rate of en-masse retraction and anchorage loss was comparable between the FM and FLM groups. Significant anchorage loss was seen with both mechanics. The result suggests that both the mechanic group require external reinforcement to prevent anchorage loss.

Comparison of Kaltenborn mobilization technique and muscle energy technique on range of motion, pain and function in subjects with chronic shoulder adhesive capsulitis.

Background: Shoulder adhesive capsulitis (AC) is a common musculoskeletal condition causing pain, loss of range of motion (ROM) in the shoulder, and a decrease in its functionality, yet poorly defined and understood since its identification. Kaltenborn mobilization technique (KMT) and muscle energy technique (MET) are commonly used physiotherapeutic techniques for their treatment. To the best of our understanding, there was no study found to compare the effectiveness of one technique over another. Objective: The objective of this study was to compare the effectiveness of KMT and MET on the ROM, pain and function in subjects with chronic shoulder AC. Methods: In this single-centred, single-blinded quasi-experimental study with a pretest-posttest design 35 subjects were randomized into two groups: Group A (n=18) received KMT and Group B (n=17) received MET along with the moist hot pack (MHP), supervised exercises and home exercises common to both the groups. A total of 32 subjects completed the study with three dropouts. Subjects were evaluated before and after 10 treatment sessions for the outcomes, shoulder external rotation passive range of motion (ER-PROM) and abduction passive range of motion (ABD-PROM) using the universal goniometer, intensity of pain using the numeric pain rating scale (NPRS) and functional disability using the shoulder pain and disability index (SPADI). Results: Analysis of 32 subjects showed that both groups were homogenous at baseline. The within-group analysis showed significant improvement (p<0.05) in both groups related to all the outcomes. But when we compared the groups, Group B showed significant (p<0.05) improvement in NPRS and SPADI in comparison to Group A. However, there was non-significant (p>0.05) difference found in ER-PROM and ABD-PROM. Conclusion: Both KMT and MET are effective in improving ROM, pain and function but MET showed a significant reduction of pain and improvement in function in subjects with chronic shoulder AC, thus supporting its use as a physiotherapeutic treatment technique.

Surveillance of central line associated bloodstream infection (CLABSI) - comparison of current (CDC/NHSN) and modified criteria: A prospective study.

Background and Aims: There is a huge load of central line-associated bloodstream infection (CLABSI) being reported in developing countries, with increased mortality and healthcare costs. Effective surveillance is a must to reduce the incidence of CLABSI. The current criteria (Centre for Disease Control and Prevention/National Healthcare Safety Network [CDC/NHSN]) for CLABSI surveillance have their own shortcomings. For diagnosing CLABSI, current CDC/NHSN CLABSI surveillance criteria are laborious and time consuming with low predictive power. Hence, modified criteria have been postulated, which are simple and implementable at resource-constrained setups. The primary objective was to compare modified criteria with CDC criteria. The secondary objective was to determine the prevalence of CRBSI. Material and Methods: A total of 98 patients with central line in situ or having the central venous line removed ≤24 hrs prior to the date of the event were enrolled. Paired blood cultures were obtained and results were analyzed using differential time to positivity. Results: The incidence of CLBSI was 8.16% and the device utilization rate was 11.6%. The negative predictive value of both the surveillance criteria was found to be excellent and comparable (96.2% for modified criteria and 97.1% for CDC criteria), therefore both can be used for screening purposes. AUC for current CDC/NHSN criteria was better than modified criteria (0.76 versus 0.66, P < 0.0001), suggesting it to be a better criterion for surveillance of CLABSI. Conclusion: Modified criteria were not superior to CDC/NHSN criteria for surveillance. Thus, there is a scope of improving the modified criteria for the purpose of surveillance. CLBSI load was higher; CLABSI bundle for prevention is thus highly recommended.

Topical creams of piperine loaded lipid nanocarriers for management of atopic dermatitis: development, characterization, and in vivo investigation using BALB/c mice model.

The aim of the research work was to investigate the efficacy of cream loaded with lipid nanocarriers (ethosomes) of piperine for the management of atopic dermatitis (AD) in comparison to conventional cream. Ethosomes of piperine were formulated with varying concentration of phosphatidylcholine and ethanol; and evaluated for entrapment efficiency (EE), sedimentation behaviour, vesicle size, zeta potential, in vitro drug release, and shape. Creams loaded with optimized ethosomal dispersion of piperine were formulated and evaluated for physicochemical parameters, ex vivo permeation and drug retention in skin layers. Similarly, conventional creams of piperine in the same concentrations were formulated and evaluated. The optimized ethosomal a conventional cream was evaluated for cytotoxicity using HaCat cell lines and in vivo on BALB/c mice model. The EE (%) and vesicle size was 74.30 ± 3.88% and 318.1 nm, respectively, for optimized ethosomal dispersion. The zeta potential was -32.6 mV and vesicles were spherical in shape. The ethosomal cream showed higher deposition in the epidermis and dermis. The creams were non-cytotoxic to HaCat cell lines. In comparison to the negative control, the ethosomal (0.1%) and conventional (0.125%) cream, both significantly decreased the ear and skin thickness, skin severity; and WBC, granulocytes, and IgE antibodies level in the BALB/c mice model. The efficacy of ethosomal cream was significantly higher than conventional cream as compared to tacrolimus (0.1%). Ethosomal cream of piperine showed good potential for the management of AD in comparison to conventional cream.

Assessment of Delirium as an Independent Predictor of Outcome among Critically Ill Patients in Intensive Care Unit: A Prospective Study.

Background: Delirium is frequently observed among critically ill patients in the intensive care unit. Although a preventable and reversible process, it is associated with greater morbidity and mortality. Early recognition and interpreting the predisposing and precipitating risk factors for delirium can improve outcomes among these patients. Objective: A prospective observational study was conducted with the primary objective to evaluate the incidence of delirium in a mixed adult intensive care unit. The secondary objectives were the evaluation of risk factors and outcomes of delirium. Methods: All patients who were more than 18 years of age and with an ICU stay of more than 24 hours were included in the study. Patients with prior history of neurological disorders, psychosis, and who were deaf were excluded. Eligible patients were evaluated by the residents to detect delirium using confusion assessment method for the intensive care unit (CAM-ICU) as a tool. Results: A total of 110 patients were included, and delirium was detected in 41 patients (37.3%). Among the predisposing risk factors, only hypertension was significantly associated with delirium. Among precipitating factors, mechanical ventilation, use of physical restraints and presence of window/natural light exposure, high Acute Physiology and Chronic Health Evaluation II scores, use of opioids, and benzodiazepines were associated with delirium. In multivariate risk regression analysis, presence of window/natural light exposure [odds ratio (OR), 55.52; 95% CI (8.887-346.904)]; (p <0.001) and duration of stay in ICU OR (1.145); 95% CI (1.058-1.238) (p = 0.001) were independent risk factors of delirium. Also, high mortality (53.7%) was observed among the delirious group of patients. Conclusion: Delirium is a common problem in the ICU and is associated with poor outcomes. Various risk factors are linked to ICU environment. How to cite this article: Junior MM, Kumar A, Kumar P, Gupta P. Assessment of Delirium as an Independent Predictor of Outcome among Critically Ill Patients in Intensive Care Unit: A Prospective Study. Indian J Crit Care Med 2022;26(6):676-681.

Halomonas icarae sp. nov., a moderately halophilic bacterium isolated from beach soil in India.

A moderately halophilic, Gram-stain-negative, aerobic bacterium, strain D1-1T, belonging to the genus Halomonas, was isolated from soil sampled at Pentha beach, Odisha, India. Phylogenetic trees reconstructed based on 16S rRNA genes and multilocus sequence analysis of gyrB and rpoD genes revealed that strain D1-1T belonged to the genus Halomonas and was most closely related to Halomonas alimentaria YKJ-16T (98.1 %) followed by Halomonas ventosae Al12T (97.5 %), Halomonas sediminicola CPS11T (97.5 %), Halomonas fontilapidosi 5CRT (97.4 %) and Halomonas halodenitrificans DSM 735T (97.2 %) on the basis of 16S rRNA gene sequence similarity. Sequence identities with other species within the genus were lower than 97.0 %. The digital DNA-DNA hybridization (dDDH) and average nucleotide identity (ANI) values of 22.4-30 % and 79.5-85.4 % with close relatives of H. halodenitrificans DSM 735T, H. alimentaria YKJ-16T, H. ventosae Al12T and H. fontilapidosi 5CRT were lower than the threshold recommended for species delineation (70 % and 95-96 % for dDDH and ANI, respectively). Further, strain D1-1T formed yellow-coloured colonies; cells were rod-shaped, motile with optimum growth at 30 °C (range, 4-45 °C) and 2-8 % NaCl (w/v; grew up to 24 % NaCl). The major fatty acids were summed feature 8 (C18 : 1 ω7c/C18 : 1 ω6c), summed feature 3 (C16 : 1 ω7c/C16 : 1 ω6c) and C16 : 0 and the main respiratory quinone was ubiquinone Q-9 in line with description of the genus. Based on its chemotaxonomic and phylogenetic characteristics and genome uniqueness, strain D1-1T represents a novel species in the genus Halomonas, for which we propose the name Halomonas icarae sp. nov., within the family Halomonadaceae. The type strain is D1-1T (=JCM 33602T=KACC 21317T=NAIMCC-B-2254T).

Ru(II)-Catalyzed, Cu(II)-mediated carbene migratory insertion in the synthesis of trisubstituted pyrroles from isoxazoles.

A convenient, "one-pot" synthesis of trisubstituted pyrroles via a Ru(ii)-catalyzed, Cu(ii)-mediated reaction of substituted isoxazoles with sulfonylhydrazones has been developed. A series of highly functionalized pyrroles are obtained via a synergistic formation of new C-C and C-N bonds. Mechanistic investigations were carried out to propose the plausible pathway. This protocol provides a facile and expeditious approach for the synthesis of various heterocyclic compounds bearing the pyrrole skeleton.

The prevalence of traumatic dental injuries in primary teeth: A systematic review and meta-analysis.

BACKGROUND/AIMS: The varied prevalence of traumatic dental injuries (TDI) in primary teeth around the globe raises a serious knowledge gap in the available literature. The aim of this study was to evaluate the prevalence of TDI in primary teeth and also to evaluate the different factors associated with TDI in primary teeth. MATERIALS AND METHODS: Comprehensive searches were performed in PubMed, Embase, Google Scholar, and The Cochrane Central Register of Controlled Trials with predefined search criteria. The primary outcome was the prevalence of TDI in primary teeth, and the secondary outcomes were the factors associated with TDI in primary teeth. Qualitative analysis was done using the Newcastle-Ottawa scale adapted for cross-sectional studies. The random-effect model was used for meta-analysis, and meta-regression analysis was done to evaluate the heterogeneity between the included studies. Meta-analysis was done using the "meta" package of "R" language. The overall quality of evidence was assessed using GRADEpro GDT software. RESULTS: A total of 24 cross-sectional studies met the inclusion criteria representing 4876 TDIs in 22 839 children aged between 0 and 6 years old. The overall prevalence of TDI in primary teeth was 24.2% (95% CI: 18.24-31.43, P = 0, I2  = 99%). Falls contributed the highest number of TDI - 59.3% (95% CI: 41.05-76.40, P < .01, I2  = 98%) - in primary teeth. The most common type of tooth fracture in primary teeth was an enamel fracture (61.9%), and prevalence of TDI in children with incompetent lip closure was 49.4%. CONCLUSION: The prevalence of TDI in cross-sectional studies of primary teeth was 24.2% with very low quality of evidence. Falls contributed the highest number of TDI in primary teeth, accounting for 59.3%. Children with incompetent lip closure have the highest prevalence (49.4%) of TDI in primary teeth.

Clinical differences of hand and rotary instrumentations during biomechanical preparation in primary teeth-A systematic review and meta-analysis.

BACKGROUND: The hand and rotary instruments are used for cleaning and shaping of root canals during biomechanical preparation in primary teeth. AIM: To determine clinical differences of hand versus rotary root canal instrumentation in primary teeth. DESIGN: Comprehensive searches were made in four electronic databases [MEDLINE (via PubMed), EMBASE, Google Scholar, and The Cochrane Central Register of Controlled Trials] till March 2020, and prospective studies that met the inclusion criteria were included. The primary outcome was instrumentation time, whereas the secondary outcomes were quality of obturation, obturation time, and clinical and radiographic success. From 604 screened studies, eleven studies qualified for meta-analysis. The random-effect model and generic inverse variance approach were used for meta-analysis. RESULTS: There was significant decrease in instrumentation time [MD-5.00 minutes (95% CI: 3.05-6.94), P < .00001, moderate evidence quality] and obturation time [MD-0.43 minutes (95% CI: 0.15-0.71), P = .003, low evidence quality] with rotary instrumentation. Optimal quality of obturation was achieved in significantly more number of teeth [risk ratio (RR) = 0.71(95% CI: 0.53-0.95),P = .02, moderate to high evidence quality] with rotary instrumentation. Similar clinical and radiographic success was observed in hand and rotary instrumentation techniques. CONCLUSION: Significant reduction in instrumentation time of five minutes was observed using rotary instrumentation with moderate quality evidence.

Neurological Manifestations of COVID-19: A Series of Seven Cases.

Identification of neurological manifestations associated with SARS-CoV-2 (severe acute respiratory syndrome coronavirus-2) in patients with no or mild pulmonary infection proves to be a challenge. The incidence of neurological associations of COVID-19 may be small as compared with respiratory disease; however, in the present scenario with an increasing number of cases each day, the overall incidence of patients with neurological manifestations and their health-related socioeconomic impact might be large. Hence it is important to report such cases so that healthcare providers and concerned authorities are aware of and may prepare for the growing burden. The literature on primary neurological manifestations of COVID-19 is limited, and hence our case series is relevant in the current scenario. The most commonly reported neurological complications are cerebrovascular accidents, encephalopathy, encephalitis, meningitis, and Guillain-Barr é syndrome (GBS). We present a series of seven cases with various neurological presentations and possible complications from this novel virus infection. HOW TO CITE THIS ARTICLE: Goel K, Kumar A, Diwan S, Kohli S, Sachdeva HC, Usha G, et al. Neurological Manifestations of COVID-19: A Series of Seven Cases. Indian J Crit Care Med 2021;25(2):219-223.

Halocatena pleomorpha gen. nov. sp. nov., an extremely halophilic archaeon of family Halobacteriaceae isolated from saltpan soil.

A novel archaeal strain designated as SPP-AMP-1T was isolated from saltpan soil, using the serial dilution method on a halophilic archaeal medium supplemented with ampicillin. Cells were both rod-shaped and pleomorphic in nature, non-motile, unable to produce acid from a variety of sugars or grow anaerobically with different substrates (l-arginine) and electron acceptors (DMSO, nitrate). Optimal growth was observed at 42 °C, 3.4-4.2 M NaCl and pH 7.2. Cells did not lyse in distilled water and grew in the absence of Mg2+ ions. Phylogenetic analysis based on the sequences of 16S rRNA gene, amino acid sequence of ß'-subunit of RNA polymerase and 400 conserved proteins retrieved from the whole genome assemblies showed that strain SPP-AMP-1T was distantly related to any existing genera within the family Halobacteriaceae. MK-8 was the only quinone detected. Polar lipid analysis showed a unique combination of diethyl derivatives of phosphatidylglycerol, phosphatidylglycerol phosphate methyl ester, glycosyl-mannosyl-glucosyl diether and sulphated glycosyl-mannosyl-glucosyl diether as the major lipids. The G+C content of genomic DNA is 57.7 mol%. The phenotypic, phylogenetic and genomic data supported the concept of the novel genus status of strain SPP-AMP-1T in the family Halobacteriaceae for which the name Halocatena pleomorpha gen. nov., sp. nov., is proposed; the type strain is SPP-AMP-1T (=JCM 31368T=KCTC 4276T=MTCC 12579T).

Probing simple structural modification of α-mangostin on its cholinesterase inhibition and cytotoxicity.

α-Mangostin has been reported to possess a broad range of pharmacological effects including potent cholinesterase inhibition, but the development of α-mangostin as a potential lead compound is impeded by its toxicity. The present study investigated the impact of simple structural modification of α-mangostin on its cholinesterase inhibitory activities and toxicity toward neuroblastoma and liver cancer cells. The dialkylated derivatives retained good acetylcholinesterase (AChE) inhibitory activities with IC50 values between 4.15 and 6.73 µM, but not butyrylcholinesterase (BChE) inhibitory activities, compared with α-mangostin, a dual inhibitor (IC50 : AChE, 2.48 µM; BChE, 5.87 µM). Dialkylation of α-mangostin produced AChE selective inhibitors that formed hydrophobic interactions at the active site of AChE. Interestingly, all four dialkylated derivatives of α-mangostin showed much lower cytotoxicity, being 6.4- to 9.0-fold and 3.8- to 5.5-fold less toxic than their parent compound on neuroblastoma and liver cancer cells, respectively. Likewise, their selectivity index was higher by 1.9- to 4.4-fold; in particular, A2 and A4 showed improved selectivity index compared with α-mangostin. Taken together, modification of the hydroxyl groups of α-mangostin at positions C-3 and C-6 greatly influenced its BChE inhibitory and cytotoxic but not its AChE inhibitory activities. These dialkylated derivatives are viable candidates for further structural modification and refinement, worthy in the search of new AChE inhibitors with higher safety margins.

Neutrophil mediated inflammatory lung damage following single Sub lethal inhalation exposure to plant protein toxin abrin in mice.

Abrin, a highly toxic plant protein found in the seeds of Abrus precatorius plant. To date, there is no antidote against abrin intoxication. Abrin is toxic by all routes of exposure, but inhalation exposure is the most toxic of all routes. Present study was conducted to evaluate the acute inhalation toxicity of aerosolized abrin in BALB/c mice. Animals were exposed to 0.2 and 0.8LC50 doses of aerosolized abrin and evaluated at 1 and 3 day post toxin exposure. Bronchoalveolar fluid from lungs was used for evaluation of markers for lung injury. Abrin inhalation exposure caused rise in LDH activity, protein content, increase in ß-glucuronidase and myeloperoxidase activity. Increase in CRP activity, MMP-9 expression and recruitment of CD11b + inflammatory cells in lungs was also observed which was associated with severe inflammation and lung damage. Histopathological findings support the lung damage after abrin exposure. Our results indicate lung injury after single aerosol inhalation exposure, associated with excessive inflammation, oxidative stress, pulmonary edema followed by lung damage. These results could supplement treatment strategies and planning for therapeutic approaches against aerosolized abrin inhalation exposure.

Comparative evaluation of antidotal efficacy of 2-PAM and HNK-102 oximes during inhalation of sarin vapor in Swiss albino mice.

Efficacy of two oximes treatments evaluated during inhalation of sarin vapor (LCt50, 755.9 mg/min/m3) in simulated real scenario in vivo. Majority of mice either became moribund or died within 1-2 min during exposure to multifold-lethal concentrations of sarin vapor. Protection indices were determined by exposing to sarin vapor in two sessions, 1 min exposure followed by treatments with or without HNK-102 (56.56 mg/kg, im) or 2-PAM (30 mg/kg, im) and atropine (10 mg/kg, ip), and again exposed for remaining 14 min. Protection offered by HNK-102 was found to be four folds higher compared to 2-PAM in the same toxic environment. Secondly, sub-lethal concentration of sarin vapor (0.8 × LCt50 or 605 mg/min/m3), 24 h post investigations revealed that the oximes could not reactivate brain and serum acetylcholinesterase (AChE) activity. The treatments prevented increase in protein concentration (p < .05) and macrophages infiltration compared to sarin alone group in broncho-alveolar lavage fluid. Lung histopathology showed intense peribronchial infiltration and edema with desquamating epithelial lining and mild to moderate alveolar septal infiltration in sarin and atropine groups, respectively. Noticeable peeling-off observed in epithelial lining and sporadic mild infiltration of epithelial cells at bronchiolar region in 2-PAM and HNK-102 groups, respectively. The oximes failed to reactivate AChE activity; however, the mice survived up to 6.0 × LCt50, proved involvement of non-AChE targets in sarin toxicity. Atropine alone treatment was found to be either ineffective or increased the toxicity. HNK-102, exhibited better survivability with lung protection, can be considered as a better replacement for 2-PAM to treat sarin inhalation induced poisoning.

Biochemical, Oxidative, and Physiological Changes Caused by Acute Exposure of Fentanyl and Its 3 Analogs in Rodents.

Synthesis and bioefficacy of fentanyl and its 8 new 1-substituted analogs (1-8) were earlier reported by us. Of these 8 compounds, N-(1-(2-phenoxyethyl)-4-piperidinyl)propionanilide (2), N-isopropyl-3-(4-( N-phenylpropionamido)piperidin-1-yl)propanamide (5), and N- t-butyl-3-(4-( N-phenylpropionamido)piperidin-1-yl) propanamide (6) were found to be more effective and less toxic compared to fentanyl. The present study reports the acute effect of fentanyl (0.50 Median Lethal Dose (LD50); intraperitoneal) and its 3 analogs (2, 5, and 6) on various biochemical and oxidative parameters in mice and various physiological parameters in rats. Blood alkaline phosphatase (1 hour and 7 days) and urea levels (1 hour) were significantly elevated by fentanyl, while alanine aminotransferase levels (1 hour) were increased by both fentanyl and analog 2 compared to the corresponding control. Increase in partial pressure of carbon dioxide and decrease in partial pressure of oxygen were also caused by fentanyl and analog 2 (1 hour). Analog 6 alone elevated malondialdehyde levels in the brain, liver, and kidney tissues (7 days). The LD50 of fentanyl and analogs 2, 5, and 6 were found to be 0.879, 87.88, 69.80, and 55.44 mg/kg, respectively, in rats. Significant decrease in heart rate, mean arterial pressure, respiratory rate (RR), and neuromuscular transmission was produced by fentanyl and analog 2, while analog 5 decreased the RR alone. The changes, particularly the respiratory depression, were found to be reversed by naloxone, a µ-receptor antagonist. Thereby, indicating involvement of µ-receptor mediated effects of the compounds. To conclude, all the analogs were found to be less toxic compared to fentanyl, suggesting their possible role in pain management.

Evaluation of evidence for pharmacokinetics-pharmacodynamics-based dose optimization of antimicrobials for treating Gram-negative infections in neonates.

BACKGROUND & OBJECTIVES: Neonates present a special subgroup of population in whom optimization of antimicrobial dosing can be particularly challenging. Gram-negative infections are common in neonates, and inpatient treatment along with critical care is needed for the management of these infections. Dosing recommendations are often extrapolated from evidence generated in older patient populations. This systematic review was done to identify the knowledge gaps in the pharmacokinetics-pharmacodynamics (PK-PD)-based optimized dosing schedule for parenteral antimicrobials for Gram-negative neonatal infections. METHODS: Relevant research questions were identified. An extensive electronic and manual search methodology was used. Potentially eligible articles were screened for eligibility. The relevant data were extracted independently in a pre-specified data extraction form. Pooling of data was planned. RESULTS: Of the 340 records screened, 24 studies were included for data extraction and incorporation in the review [carbapenems - imipenem and meropenem (n=7); aminoglycosides - amikacin and gentamicin (n=9); piperacillin-tazobactam (n=2); quinolones (n=2); third- and fourth-generation cephalosporins (n=4) and colistin nil]. For each of the drug categories, the information for all the questions that the review sought to answer was incomplete. There was a wide variability in the covariates assessed, and pooling of results could not be undertaken. INTERPRETATION & CONCLUSIONS: There is a wide knowledge gap for determining the doses of antimicrobials used for Gram-negative infections in neonates. A different profile of newborns in the developing countries could affect the disposition of antimicrobials for Gram negative infections, necessitating the generation of PK-PD data of antimicrobials in neonates from developing countries. Further, guidelines for treatment of neonatal conditions may incorporate the evidence-based PK-PD-guided dosing regimens.

Membrane Binding of Parkinson's Protein α-Synuclein: Effect of Phosphorylation at Positions 87 and 129 by the S to D Mutation Approach.

Human α-synuclein, a protein relevant in the brain with so-far unknown function, plays an important role in Parkinson's disease. The phosphorylation state of αS was related to the disease, prompting interest in this process. The presumed physiological function and the disease action of αS involves membrane interaction. Here, we study the effect of phosphorylation at positions 87 and 129, mimicked by the mutations S87A, S129A (nonphosphorylated) and S87D, S129D (phosphorylated) on membrane binding. Local binding is detected by spin-label continuous-wave electron paramagnetic resonance. For S87A/D, six positions (27, 56, 63, 69, 76, and 90) are probed; and for S129A/D, three (27, 56, and 69). Binding to large unilamellar vesicles of 100 nm diameter of 1-palmitoyl-2-oleoyl-sn-glycero-3-phospho-(1'-rac-glycerol) and 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine in a 1 : 1 composition is not affected by the phosphorylation state of S129. For phosphorylation at S87, local unbinding of αS from the membrane is observed. We speculate that modulating the local membrane affinity by phosphorylation could tune the way αS interacts with different membranes; for example, tuning its membrane fusion activity.

Topography evolution of 500 keV Ar(4+) ion beam irradiated InP(100) surfaces - formation of self-organized In-rich nano-dots and scaling laws.

We report the formation of self-organized nano-dots on the surface of InP(100) upon irradiating it with a 500 keV Ar(4+) ion beam. The irradiation was carried out at an angle of 25° with respect to the normal at the surface with 5 different fluences ranging from 1.0 × 10(15) to 1.0 × 10(17) ions per cm(2). The morphology of the ion-irradiated surfaces was examined by atomic force microscopy (AFM) and the formation of the nano-dots on the irradiated surfaces was confirmed. The average size of the nano-dots varied from 44 ± 14 nm to 94 ± 26 nm with increasing ion fluence. As a function of the ion fluence, the variation in the average size of the nano-dots has a great correlation with the surface roughness, which changes drastically up to the ion fluence of 1.0 × 10(16) ions per cm(2) and attains almost a saturation level for further irradiation. The roughness and the growth exponent values deduced from the scaling laws suggest that the kinetic sputtering and the large surface diffusion steps of the atoms are the primary reasons for the formation of the self-organized nanodots on the surface. X-ray photo-electron spectroscopy (XPS) studies show that the surface stoichiometry changes with the ion fluence. With irradiation, the surface becomes more indium (In)-rich owing to the preferential sputtering of the phosphorus atoms (P) and the pure metallic In nano-dots evolve at the highest ion fluence. The cross-sectional scanning electron microscopy (SEM) analysis of the sample irradiated with the highest fluence showed the absence of the nanostructuring beneath the surface. The surface morphological changes at this medium energy ion irradiation are discussed in correlation with the low and high energy experiments to shed more light on the mechanism of the well separated nano-dot formation.

Protein docking using an ensemble of spin labels optimized by intra-molecular paramagnetic relaxation enhancement.

Paramagnetic NMR is a useful technique to study proteins and protein complexes and the use of paramagnetic relaxation enhancement (PRE) for this purpose has become wide-spread. PREs are commonly generated using paramagnetic spin labels (SLs) that contain an unpaired electron in the form of a nitroxide radical, with 1-oxyl-2,2,5,5-tetramethyl-2,5-dihydropyrrol-3-ylmethyl methane thiosulfonate (MTSL) being the most popular tag. The inherent flexibility of the SL causes sampling of several conformations in solution, which can be problematic as over- or underestimation of the spatial distribution of the unpaired electron in structural calculations will lead to errors in the distance restraints. We investigated the effect of this mobility on the accuracy of protein-protein docking calculations using intermolecular PRE data by comparing MTSL and the less mobile 3-methanesulfonilthiomethyl-4-(pyridin-3-yl)-2,2,5,5-tetramethyl-2,5-dihydro-1H-pyrrol-1-yloxyl (pyMTSL) on the dynamic complex of cytochrome c and cytochrome c peroxidase. No significant differences were found between the two SLs. Docking was performed using either single or multiple conformers and either fixed or flexible SLs. It was found that mobility of the SLs is the limiting factor for obtaining accurate solutions. Optimization of SL conformer orientations using intra-molecular PRE improves the accuracy of docking.