Structure of Rhizobium sp. 4-9 histamine dehydrogenase and analysis of the electron transfer pathway to an abiological electron acceptor.

Histamine dehydrogenase from the gram-negative bacterium Rhizobium sp. 4-9 (HaDHR) is a member of a small family of dehydrogenases containing a covalently attached FMN, and the only member so far identified to date that does not exhibit substrate inhibition. In this study, we present the 2.1 Å resolution crystal structure of HaDHR. This new structure allowed for the identification of the internal electron transfer pathway to abiological ferrocene-based mediators. Alanine 437 was identified as the exit point of electrons from the Fe4S4 cluster. The enzyme was modified with a Ser436Cys mutation to facilitate covalent attachment of a ferrocene moiety. When modified with Fc-maleimide, this new construct demonstrated direct electron transfer from the enzyme to a gold electrode in a histamine concentration-dependent manner without the need for any additional electron mediators.

Evaluation of AIIMS Modified INCLEN Tool for Diagnosis of Epilepsy.

OBJECTIVES: To evaluate the AIIMS Modified INCLEN tool for the diagnosis of epilepsy. METHODS: This cross-sectional study enrolled 250 children aged 1 month to 18 years presenting with complaints of abnormal body movements to either the pediatric or neurology outpatient departments in our institution between October 1, 2018 and June 30, 2020. The All India Institute of Medical Sciences (AIIMS) modified International Clinical Epidemiology Network (INCLEN) diagnostic tool for epilepsy (AIIMS modified INDT-EPI) was administered and a diagnosis was made, which was further verified by a pediatrician or a neurologist. Specificity, sensitivity, positive predictive value (PPV) and negative predictive value (NPV) were calculated. RESULTS: The study tool had a sensitivity of 87.6% and specificity of 84.0%. The PPV and NPV of the study tool were 86.8% and 84.9%, respectively. CONCLUSION: The study tool has good psychometric properties for physician assessment with regard to diagnosis of epilepsy.

Administration of Protamine Through Radial Arterial Access: A Prospective Observational Study.

Protamine is mainly used to reverse the anticoagulant effect of heparin after cardiopulmonary bypass (CPB). Unfortunately, it is associated with adverse clinical reactions ranging from minor cardiopulmonary instability to fatal cardiovascular collapse. In the present prospective observational study, effects of protamine administration through peripheral intra-arterial route, i.e., radial artery, were investigated.

A Review on Mixed Matrix Membranes for Solvent Dehydration and Recovery Process.

Solvent separation and dehydration are important operations for industries and laboratories. Processes such as distillation and extraction are not always effective and are energy-consuming. An alternate approach is offered by pervaporation, based on the solution-diffusion transport mechanism. Polymer-based membranes such as those made of Polydimethylsiloxane (PDMS) have offered good pervaporation performance. Attempts have been made to improve their performance by incorporating inorganic fillers into the PDMS matrix, in which metal-organic frameworks (MOFs) have proven to be the most efficient. Among the MOFs, Zeolitic imidazolate framework (ZIF) based membranes have shown an excellent performance, with high values for flux and separation factors. Various studies have been conducted, employing ZIF-PDMS membranes for pervaporation separation of mixtures such as aqueous-alcoholic solutions. This paper presents an extensive review of the pervaporation performance of ZIF-based mixed matrix membranes (MMMs), novel synthesis methods, filler modifications, factors affecting membrane performance as well as studies based on polymers other than PDMS for the membrane matrix. Some suggestions for future studies have also been provided, such as the use of biopolymers and self-healing membranes.

An active site mutation in 6-hydroxy-l-Nicotine oxidase from Arthrobacter nicotinovorans changes the substrate specificity in favor of (S)-nicotine.

The enzyme 6-Hydroxy-l-Nicotine oxidase (HLNO) is a flavin-dependent enzyme that catalyzes the first step in the pyridine pathway of oxidation of nicotine as a source of energy and nitrogen in several bacteria. Recombinant Arthrobacter nicotinovorans HLNO also catalyzes oxidation of (s)-nicotine at a low but measurable rate (Fitzpatrick et al., 2016, Biochemistry 55, 697-703). Rational design and bioinformatics approaches, based on the known high-resolution structure of this enzyme (RCSB: 3NG7), were employed to further enhance the catalytic turnover and stability of the enzyme using (S)-nicotine as substrate. The active site residue Tyr311 forms a hydrogen bond with the hydroxyl group of (S)-6-OH-nicotine within the catalytic pocket. Its replacement by a tryptophan residue reduced the kcat for (S)-6-OH-nicotine by more than 6-fold and increased ~1.5-fold. Combining this mutation with two surface mutations that were predicted to enhance enzyme stability, further increased the kcat for nicotine resulting in a comparatively robust oxidation of (s)-nicotine (kcat >1 s-1) at 37 °C, at the same time reducing the specificity for (S)-OH-nicotine (kcat/KM) by more than 100-fold and increasing that for (S)-nicotine by more than 2-fold. Interestingly, adding a maltose-binding protein (MBP) tag onto the N-terminus of HLNO markedly increased the thermal stability of the enzyme, extending the half-life at 37 °C from ~2 h to ~22 h. This effect was due almost entirely to increased FAD retention, an observation that may prove useful to improve flavin retention in other flavin-dependent monoamine oxidases.

Perioperative anaesthetic concerns in transgender patients: Indian perspective.

Medical care of transgender patients is not only legally bound but also ethically required. Globally, 0.5%-0.9% of the adult population exhibits a gender different from their birth sex, but there is a dearth of transgender-friendly hospitals stemming from ignorance to disdain for this marginalised community. With gradually increasing acceptance of the transgender patients in the society, healthcare professionals must gear up to deal with issues specific and unique to this group of population. These concerns remain important to understand for an optimal perioperative care. The medical concerns transcend international boundaries, whereas legal, social, economic and psychological concerns vary from place to place. There is a need for modification of curriculum and training for healthcare personnel to foster sensitivity and empathy in patient dealing, to allow for an unbiased optimal healthcare. Such patients require a thorough assessment in a comfortable environment considering their specific needs. A plan for perioperative care needs to be done and discussed with the patient and the perioperative care team as well. There is scarce literature with regard to perioperative care in the transgender patients and hence requires more research.

Evaluation extracellular matrix-chitosan composite films for wound healing application.

The present study describes the preparation of extracellular matrix (ECM; from porcine omentum) based chitosan composite films for wound dressing applications. The films were prepared by varying the ECM content, whereas, the amount of chitosan was kept constant. The interactions amongst the components of the films were analyzed by FTIR and XRD studies. The films were thoroughly characterized for surface hydrophilicity, moisture retention capability, water vapor permeability, mechanical and biocompatibility. FTIR study indicated that both chitosan and ECM were present in their native form and did not lose their activity. XRD analysis suggested composition dependent change in the crystallinity of the films. The mechanical properties suggested that the composite films had sufficient properties to be used for wound dressing applications. An increase in the ECM content resulted in better hydrophilicity of the films and hence better the moisture retention capacity and retardant water vapor transmission rate property of the composite films. The films were found to be biocompatible to both blood and adipose tissue derived stem cells. In gist, the prepared films may be explored as wound dressing materials.

Olanzapine-induced neuroleptic malignant syndrome in a patient with bipolar affective disorder: Does quetiapine holds the solution?

Neuroleptic Malignant Syndrome (NMS) is a rare, severe and life threatening condition induced by antipsychotic medications. It is commonly encountered with the use of first generation antipsychotics, however cases of NMS have been reported with the use of second generation antipsychotics like Olanzapine, Risperidone, Paliperidone, Aripiprazole, Ziprasidone, Amisulpride, Quetiapine and Clozapine, though the incidence of such reports is rare. Due to decreased use of first generation antipsychotics, NMS is reported less frequently now a days. In this case report- we highlight the management issues of a patient suffering from bipolar affective disorder, who had developed NMS following intramuscular injection of haloperidol, which was withdrawn and olanzapine was given later on. The patient had again developed NMS with olanzapine. Finally the patient was managed with modified electroconvulsive therapy and discharged on Lithium carbonate and Quetiapine.