Human B-cell Ontogeny in Humanized NOD/SCID γcnull^{null} Mice Generates a Diverse Yet Auto/Poly- and HIV-1 Reactive Antibody Repertoire

Characterization of the human antibody (Ab) repertoire in mouse models of the human immune system is essential to establish their relevance in translational studies. Single human B-cells were sorted from bone marrow and periphery of humanized NOD/SCID γc$^{null}$ mice at 8–10 months post-engraftment with human cord blood-derived CD34$^+$ stem cells. Human immunoglobulin variable heavy (V$_H$) and kappa (V$_κ$) genes were amplified, cognate V$_H$-V$_κ$ gene-pairs assembled as single-chain variable fragment-Fc antibodies (scFvFcs) and functional studies performed. Although overall distribution of V$_H$ genes approximated the normal human Ab repertoire, analysis of the V$_H$-third complementarity determining regions (H-CDR3) in the mature B-cell subset demonstrated an increase in length and positive charges suggesting autoimmune characteristics. Additionally, >70% of Vκ sequences utilized V$_κ$4-1, a germline gene associated with autoimmunity. The mature B-cell subset-derived scFvFcs displayed the highest frequency of autoreactivity and polyspecificity, suggesting defects in checkpoint control mechanisms. Furthermore, these scFvFcs demonstrated binding to recombinant HIV envelope corroborating previous observations of poly/autoreactivity in anti-HIVgp140 antibodies. These data lend support to the hypothesis that anti-HIV BnAbs may be derived from auto/polyspecific Abs that escaped immune elimination and that the hNSG mouse could provide a new experimental platform for studying the origin of anti-HIV neutralizing Ab responses

Stability-indicating HPLC determination of pramipexole dihydrochloride in bulk drug and pharmaceutical dosage form

A novel stability-indicating high-performance liquid chromatographic assay method was developed and validated for quantitative determination of pramipexole dihydrochloride in bulk drugs and in pharmaceutical dosage form in the presence of degradation products. An isocratic, reversed phase HPLC method was developed to separate the drug from the degradation products, using an Ace5-C18 (250×4.6 mm, 5 µm) advance chromatography column, and 10 mmol L-1 ammonium acetate and acetonitrile (75:25 v/v) as a mobile phase. The detection was carried out at a wavelength of 260 nm. The pramipexole was subjected to stress conditions of hydrolysis (acid, base), oxidation, photolysis and thermal degradation. Degradation was observed for pramipexole in base, in acid and in 30% H2O2. The drug was found to be stable in the other stress conditions attempted. The degradation products were well resolved from the main peak. The percentage recovery of pramipexole was from (99.87 to 99.98%) in the pharmaceutical dosage form. The developed method was validated with respect to linearity, accuracy (recovery), precision, system suitability, specificity and robustness. The forced degradation studies prove the stability indicating power of the method

Effect of previous scorpion bite(s) on the action of intrathecal bupivacaine: A case control study

Background: During the routine practice in the institution, it was observed that there were persistent incidents of inadequate/failed spinal anaesthesia in patients with a history of single or multiple scorpion bite/s. To test any possible correlation between scorpion bite and the altered response to spinal anaesthesia, a case control study was conducted involving patients with a history of scorpion bite/s and without such a history. Methods: Randomly selected 70 (n=70) patients of either sex and age range of 18-80 years, were divided into two equal groups, giving past history of one or multiple scorpion bites and giving no such a history. The anaesthetic management was identical inclusive of subarachnoid block with 3.5 ml. 0.5% bupivacaine heavy. The onsets of sensory, motor and peaks of sensory and motor blocks were observed with the pin-prick method and Bromage scale. After waiting for 20 min, if the block was inadequate, then balanced general anaesthesia was administered. The analysis of the data and application of various statistical tests was carried out using Chi-square test, percentages, independent sample t-test and paired t-test. Results: Demographically both groups were comparable. In scorpion bite group, the time of onsets of both sensory and motor blocks and time for the peak of sensory and motor blocks were significantly prolonged, 4 patients had failed/inadequate sensory block and 5 patients had failed/inadequate motor block while all the patients in non-bite group had adequate intra-operative block. Conclusion: We conclude that there appears to be a direct correlation between the histories of old, single or multiple scorpion bites and development of resistance to effect of local anaesthetics administered intra-thecally

Estimation of spectral response of a consumer grade digital still camera and its application for temperature measurement

703-707Consumer grade digital still camera has been used for image acquisition of various heat sources and the spectral response of camera has been obtained. Different sources are used to cover the bandwidth ranging from IR to UV. From the results, it has been observed that the response of the digital camera used to capture source images is adequate to cover visible range (400-700 nm). The images of various visible known heat sources are captured using the mentioned camera. From the captured images, various zones of the source are identified using image-processing algorithms. The actual temperature is measured by placing a miniature k type thermocouple in each zone. The measured temperature values are correlated with the respective colours and features computed from the images. The colour temperature correlation is established by applying various analytical techniques. Calibration of the image-based measurement with contact measurement using an established sensor is performed. </b

Impact of an antimicrobial stewardship and monitoring of infection control bundle in a surgical intensive care unit of a tertiary-care hospital in India

Objectives: Antimicrobial stewardship (AMS) in resource-limited settings lacks models that can be readily adapted to their settings. Here we discuss the impact of a combined strategy of AMS and monitoring of infection control practices in a tertiary-care centre of a developing country. Methods: This study was undertaken in the surgical unit of a tertiary-care hospital over an 8-month period. In the first 2 months (baseline phase), prospective audit and feedback alone was undertaken, while in the next 6 months (intervention phase) this was supplemented with strategies such as antimicrobial timeout, correction of doses and bundle approach for prevention of hospital-acquired infections. Results: A total of 337 patients were included (94 in the baseline phase and 243 in the intervention phase). There was a decrease in days of therapy per 1000 patient-days (1000PD) (1112.3 days vs. 1048.6 days), length of therapy per 1000PD (956 days vs. 936.3 days) and defined daily doses (DDD) per 1000PD for most antimicrobials. A decrease in double cover for Gram-negative infections (9.6% vs. 2.9%) but an increase in double anaerobic cover (4.2% vs. 7.4%) was observed. There was a decrease in the incidence of ventilator-associated pneumonia per 1000 ventilator-days in the intervention phase (46.4 vs. 35.4), whereas central line-associated bloodstream infections per 1000 central line-days remained the same (14.7 vs. 14.8). Conclusion: This study shows that implementation of routine AMS activities with monitoring of infection control practices can help decrease overall antimicrobial use. With furtherance of measures to control infection, antimicrobial use may be further curtailed

Assessment of Appropriateness of Antimicrobial Therapy in Resource-Constrained Settings: Development and Piloting of a Novel Tool—AmRAT

Inappropriate antimicrobial prescribing is considered to be the leading cause of high burden of antimicrobial resistance (AMR) in resource-constrained lower- and middle-income countries. Under its global action plan, the World Health Organization has envisaged tackling the AMR threat through promotion of rational antibiotic use among prescribers. Given the lack of consensus definitions and other associated challenges, we sought to devise and validate an Antimicrobial Rationality Assessment Tool—AmRAT—for standardizing the assessment of appropriateness of antimicrobial prescribing. A consensus algorithm was developed by a multidisciplinary team consisting of intensivists, internal medicine practitioners, clinical pharmacologists, and infectious disease experts. The tool was piloted by 10 raters belonging to three groups of antimicrobial stewardship (AMS) personnel: Master of Pharmacology (M.Sc.) (n = 3, group A), Doctor of Medicine (MD) residents (n = 3, group B), and DM residents in clinical pharmacology (n = 4, group C) using retrospective patient data from 30 audit and feedback forms collected as part of an existing AMS program. Percentage agreement and the kappa (κ) coefficients were used to measure inter-rater agreements amongst themselves and with expert opinion. Sensitivity and specificity estimates were analyzed comparing their assessments against the gold standard. For the overall assessment of rationality, the mean percent agreement with experts was 76.7% for group A, 68.9% for group B, and 77.5% for group C. The kappa values indicated moderate agreement for all raters in group A (κ 0.47–0.57), and fair to moderate in group B (κ 0.22–0.46) as well as group C (κ 0.37–0.60). Sensitivity and specificity for the same were 80% and 68.6%, respectively. Though evaluated by raters with diverse educational background and variable AMS experience in this pilot study, our tool demonstrated high percent agreement and good sensitivity and specificity, assuring confidence in its utility for assessing appropriateness of antimicrobial prescriptions in resource-constrained healthcare environments