Linezolid Pharmacokinetic-Anemia Modeling in Children with Rifampicin-Resistant Tuberculosis.

BACKGROUND: Linezolid, an important component of rifampicin- and multidrug-resistant tuberculosis (RR/MDR-TB) treatment, is associated with treatment-limiting toxicities, including anemia. Patient-level and linezolid pharmacokinetic risk factors for anemia have not been well described in children treated for RR/MDR-TB. METHODS: We evaluated the pharmacokinetics of linezolid and longitudinal hemoglobin data to validate an existing population linezolid pharmacokinetic model. We assessed the impact of linezolid pharmacokinetics and the risk of developing anemia in a prospectively enrolled cohort of children. The validation of a previously published population pharmacokinetic linezolid model used nonlinear mixed effects modeling. A multivariable ordinal logistic regression model was built to predict the incidence of anemia. RESULTS: A total of 112 children, median age 7.2 (IQR: 2.2-16.3) years, were included from South Africa (n=87) and India (n=25). Of these, 24 children contributed new linezolid pharmacokinetic data. The population pharmacokinetic model which informs the currently recommended linezolid dosing in children (10-15 mg/kg) was validated with these additional new data. For every 1 g/dL lower baseline hemoglobin, the odds of developing grade 3 or 4 anemia increased by 2.64 (95% CI 1.98-3.62). For every 1 mg/L*h higher linezolid area under the concentration-time curve (AUC), the odds of developing a grade 3 or 4 anemia increased by 1.012 (95% CI 1.007-1.017). CONCLUSIONS: These data taken together, confirm currently recommended linezolid doses in children. The risk of anemia in children should be carefully considered and monitored throughout. Initiating linezolid in children with low baseline hemoglobin increases the probability of experiencing grade 3 or 4 anemia.

Vanishing lung syndrome a rare cause of dwindling of lungs in children with pulmonary tuberculosis.

Vanishing lung syndrome (VLS) or idiopathic giant bullous disease is a rare condition characterized by giant emphysematous bullae, classically presenting as a slowly enlarging bulla that compresses normal lung parenchyma and causes mediastinal shift, leading to increasing dyspnea and reduced exercise tolerance. Intermittent sudden worsening of symptoms may be seen because of secondary pneumothorax due to rupture of these bullae. Here we present three cases of vanishing lung syndrome in children due to tuberculosis (TB). Reports on VLS due to TB are bare minimum. In contrast to most of the published case reports, our cases had a moderate to rapid progression, bilateral extensive bullae and isoniazid which has been traditionally thought to be the causative factor was not used in one of our patients. All three are female patients arising new horizons of research regarding whether there is any sex predominance.

Spin Dynamics across Metallic Layers on the Few-Femtosecond Timescale.

We measure the light-driven response of a magnetic multilayer structure made of thin alternating layers of cobalt and platinum at the few-femtosecond timescale. Using attosecond magnetic circular dichroism, we observe how light rearranges the magnetic moment during and after excitation. The results reveal a sub-5 fs spike of magnetization in the platinum layer, which follows the shape of the driving pulse. With the help of time-dependent density functional theory, we interpret the observations as light-driven spin injection across the metallic layers of the structure. The light-triggered spin current is strikingly short, largely outpacing decoherence and dephasing. The findings suggest that the ability of shaping light fields in refined ways could be translated into shaping new forms of spin currents in materials.

Pharmacokinetics of anti-TB drugs in children and adolescents with drug-resistant TB: a multicentre observational study from India.

BACKGROUND: Drug-resistant tuberculosis (DR-TB) is one of the challenging forms of TB to treat, not only in adults but also in children and adolescents. Further, there is a void in the treatment strategy exclusively for children due to various reasons, including paucity of pharmacokinetic (PK) data on anti-TB drugs across the globe. In this context, the present study aimed at assessing the PK of some of the anti-TB drugs used in DR-TB treatment regimens. METHOD: A multicentre observational study was conducted among DR-TB children and adolescents (n = 200) aged 1-18 years (median: 12 years; IQR: 9-14) treated under programmatic settings in India. Steady-state PK (intensive: n = 89; and sparse: n = 111) evaluation of moxifloxacin, levofloxacin, cycloserine, ethionamide, rifampicin, isoniazid and pyrazinamide was carried out by measuring plasma levels using HPLC methods. RESULTS: In the study population, the frequency of achieving peak plasma concentrations ranged between 13% (for rifampicin) to 82% (for pyrazinamide), whereas the frequency of suboptimal peak concentration for pyrazinamide, cycloserine, moxifloxacin, levofloxacin and rifampicin was 15%, 19%, 29%, 41% and 74%, respectively. Further, the frequency of supratherapeutic levels among patients varied between 3% for pyrazinamide and 60% for isoniazid. In the below-12 years age category, the median plasma maximum concentration and 12 h exposure of moxifloxacin were significantly lower than that of the above-12 years category despite similar weight-adjusted dosing. CONCLUSIONS: Age significantly impacted the plasma concentration and exposure of moxifloxacin. The observed frequencies of suboptimal and supratherapeutic concentrations underscore the necessity for dose optimization and therapeutic drug monitoring in children and adolescents undergoing DR-TB treatment.

Nurturing Tomorrow's Antibiotic Stewards: An Innovative School Campaign to Combat Antimicrobial Resistance in Delhi.

SUMMARY: Antimicrobials are lifesaving medicines, but their misuse drives antimicrobial resistance. Schools, as educational hubs wield transformative potential in fostering responsible antimicrobial behavior among students and the broader community. An online campaign targeted Delhi schools, training teachers as master trainers who, in turn, educated 359,940 students. Significant pre- to post-test score improvements were observed among teachers (6.98-8.14; P < 0.01) and students (5.20-6.56; P < 0.01). The campaign received excellent feedback (85%), with 966 students participating in the "IDEAthon" competition. While a single session improved knowledge, continuous engagement and activities are imperative for sustained behavioral change in antibiotic usage.

Spin vacuum switching.

Ultrafast control over the magnetic orientation of matter represents a vital element of potential future spin-based electronics ("spintronics"). While physical mechanisms underpinning spin switching are established for picosecond time scales, we here present a physical route to magnetization toggle control, i.e., multiple switching events, at <100 femtoseconds. A minority spin current injected into a ferromagnet is shown to generate rapid depopulation of the minority channel below the ground-state Fermi level, creating a minority "spin vacuum" that then drives rapid charge redistribution from the majority channel and spin switching. We demonstrate that this mechanism reproduces many of the features of recent subpicosecond switching of ferromagnetic Co/Pt multilayers and provide simple practical rules for the design of materials via tailoring the electronic density of states to optimize spin vacuum control over magnetic order.

Predicting efficacy of antiseizure medication treatment with machine learning algorithms in North Indian population.

PURPOSE: This study aimed to develop a classifier using supervised machine learning to effectively assess the impact of clinical, demographical, and biochemical factors in accurately predicting the antiseizure medications (ASMs) treatment response in people with epilepsy (PWE). METHODS: Data was collected from 786 PWE at the Outpatient Department of Neurology, Institute of Human Behavior and Allied Sciences (IHBAS), New Delhi, India from 2005 to 2015. Patients were followed up at the 2nd, 4th, 8th, and 12th month over the span of 1 year for the drugs being administered and their dosage, the serum drug levels, the frequency of seizure control, drug efficacy, the adverse drug reactions (ADRs), and their compliance to ASMs. Several features, including demographic details, medical history, and auxiliary examinations electroencephalogram (EEG) or Computed Tomography (CT) were chosen to discern between patients with distinct remission outcomes. Remission outcomes were categorized into 'good responder (GR)' and 'poor responder (PR)' based on the number of seizures experienced by the patients over the study duration. Our dataset was utilized to train seven classical machine learning algorithms i.e Extreme Gradient Boost (XGB), K-Nearest Neighbor (KNN), Support Vector Classifier (SVC), Decision Tree (DT), Random Forest (RF), Naïve Bayes (NB) and Logistic Regression (LR) to construct classification models. RESULTS: Our research findings indicate that 1) among the seven algorithms examined, XGB and SVC demonstrated superior predictive performances of ASM treatment outcomes with an accuracy of 0.66 each and ROC-AUC scores of 0.67 (XGB) and 0.66 (SVC) in distinguishing between PR and GR patients. 2) The most influential factor in discerning PR to GR patients is a family history of seizures (no), education (literate) and multitherapy with Chi-square (χ2) values of 12.1539, 8.7232 and 13.620 respectively and odds ratio (OR) of 2.2671, 0.4467, and 1.9453 each. 3). Furthermore, our surrogate analysis revealed that the null hypothesis for both XGB and SVC was rejected at a 100 % confidence level, underscoring the significance of their predictive performance. These findings underscore the robustness and reliability of XGB and SVC in our predictive modelling framework. SIGNIFICANCE: Utilizing XG Boost and SVC-based machine learning classifier, we successfully forecasted the likelihood of a patient's response to ASM treatment, categorizing them as either PR or GR, post-completion of standard epilepsy examinations. The classifier's predictions were found to be statistically significant, suggesting their potential utility in improving treatment strategies, particularly in the personalized selection of ASM regimens for individual epilepsy patients.

Evaluation of AAICare®-TB sequence analysis tool for accurate diagnosis of drug-resistant tuberculosis: A comparative study with TB-Profiler and Mykrobe.

A rapid and comprehensive drug susceptibility test is essential for eliminating drug resistant tuberculosis. Next generation sequencing (NGS) based susceptibility testing is being explored as a potential substitute for the conventional phenotypic and genotypic testing methods. However, the adoption of NGS based genotypic susceptibility testing depends on the availability of simple, accurate and efficient analysis tools. This preliminary study aimed to evaluate the performance of a Mycobacterium tuberculosis (Mtb) genome analysis pipeline, AAICare®-TB, for susceptibility prediction, in comparison to two widely used gDST prediction tools, TB-Profiler and Mykrobe. This study was performed in a National Reference Laboratory in India on presumptive drug-resistant tuberculosis (DR-TB) isolates. Whole genome sequences of the 120 cultured isolates were obtained through Illumina sequencing on a MiSeq platform. Raw sequences were simultaneously analysed using the three tools. Susceptibility prediction reports thus generated, were compared to estimate the total concordance and discordance. WHO mutation catalogue (1st edition, 2021) was used as the reference standard for categorizing the mutations. In this study, AAICare®-TB was able to predict drug resistance status for First Line (Streptomycin, Isoniazid, Rifampicin, Ethambutol and Pyrazinamide) and Second Line drugs (Fluoroquinolones, Second Line Injectables and Ethionamide) in 93 samples along with lineage and hetero-resistance as per the WHO guidelines.

Hypothyroidism presenting as a fissure tongue.

We are reporting a case of hypothyroidism presenting as fissured tongue, demonstrating significant resolution of fissure tongue upon thyroid hormone replacement therapy.

Light-Shaping of Valley States.

The established paradigm to create valley states, excitations at local band extrema ("valleys"), is through selective occupation of specific valleys via circularly polarized laser pulses. Here we show a second way exists to create valley states, not by valley population imbalance but by "light-shaping" in momentum space, i.e. controlling the shape of the distribution of excited charge at each valley. While noncontrasting in valley charge, such valley states are instead characterized by a valley current, identically zero at one valley and finite and large at the other. We demonstrate that these (i) are robust to quantum decoherence, (ii) allow lossless toggling of the valley state with successive femtosecond laser pulses, and (iii) permit valley contrasting excitation both with and without a gap. Our findings open a route to robust ultrafast and switchable valleytronics in a wide scope of 2d materials, bringing closer the promise of valley-based electronics.

Giant and Controllable Valley Currents in Graphene by Double Pumped THz Light.

The field of valleytronics considers the creation and manipulation of "valley states", charge excitations characterized by a particular value of the crystal momentum in the Brillouin zone. Here we show, using the example of minimally gapped (≤40 meV) graphene, that there exist lightforms that create almost perfect valley contrasting current states (up to ∼80% valley purity) in the absence of a valley contrasting charge excitation. These "momentum streaked" THz waveforms act by deforming the excited state population in momentum space such that current flows at one valley yet is blocked at the conjugate valley. This approach both unlocks the potential of graphene as a materials platform for valleytronics, as gaps of 10-40 meV are robustly found in useful experimental contexts such as graphene/hBN systems, while simultaneously providing a tool toward ultrafast light control of valley currents in diverse minimally gapped matter, including many topological insulator systems.

Expected and Unexpected Products from the Biochemical Oxidation of Bacterial Alkylquinolones with CYP4F11.

2-Alkylquinolones are a class of microbial natural products primarily produced in the Pseudomonas and Burkholderia genera that play a key role in modulating quorum sensing. Bacterial alkylquinolones were synthesized and then subjected to oxidative biotransformation using human cytochrome P450 enzyme CYP4F11, heterologously expressed in the fission yeast Schizosaccharomyces pombe. This yielded a range of hydroxylated and carboxylic acid derivatives which had undergone ω-oxidation of the 2-alkyl chain, the structures of which were determined by analysis of NMR and MS data. Oxidation efficiency depended on chain length, with a chain length of eight or nine carbon atoms proving optimal for high yields. Homology modeling suggested that Glu233 was relevant for binding, due to the formation of a hydrogen bond from the quinolone nitrogen to Glu233, and in this position only the longer alkyl chains could come close enough to the heme moiety for effective oxidation. In addition to the direct oxidation products, a number of esters were also isolated, which was attributed to the action of endogenous yeast enzymes on the newly formed ω-hydroxy-alkylquinolones. ω-Oxidation of the alkyl chain significantly reduced the antimicrobial and antibiofilm activity of the quinolones.

GeneXpert Ultra in Urine Samples for Diagnosis of Extra-Pulmonary Tuberculosis.

Extra-pulmonary tuberculosis (EPTB) continues to be difficult to diagnose. Novel biomarkers in biological specimens offer promise. Detection of Mycobacterium tuberculosis (Mtb) DNA in urine could prove useful in diagnosis of EPTB, possibly due to disseminated disease or micro-abscesses reported in kidneys. The current study was designed to detect Mtb DNA in stored urine samples from patients with EPTB. Diagnosis of EPTB was reached using Microbiological Reference Standards (MRS) on samples from the disease site using WHO Recommended Diagnostics (WRD), [smear microscopy, liquid culture (MGIT-960)] and GX (molecular WRD, mWRD) and Comprehensive reference standards [CRS, clinical presentation, microbiological reference standards, radiology, histopathology]. GX-Ultra was performed on urine samples stored in -80oC deep freezer, retrospectively. Of 70 patients, 51 (72.9%) were classified as confirmed TB, 11 (15.7%) unconfirmed TB, and 8 (11.4%) unlikely TB. GX-Ultra in urine samples demonstrated sensitivity of 52.9% and specificity of 57.9% against MRS, and higher sensitivity of 56.5% and specificity of 100% against CRS. The sensitivity and specificity of GX-Ultra in urine was 53.6% and 75% for pus sample subset and 52.2% and 53.3% for fluid sample subset. Urine being non-invasive and easy to collect, detection of Mtb DNA using mWRD in urine samples is promising for diagnosis of EPTB.

Mutual Modulation of the Activities of Human CYP2D6 and Four UGTs during the Metabolism of Propranolol.

Cytochromes P450 (CYP) and UDP-glucuronosyltransferases (UGT) are two enzyme families that play an important role in drug metabolism, catalyzing either the functionalization or glucuronidation of xenobiotics. However, their mutual interactions are poorly understood. In this study, the functional interactions of human CYP2D6 with four human UGTs (UGT1A7, UGT1A8, UGT1A9, and UGT2A1) were investigated using our previously established co-expression model system in the fission yeast Schizosaccharomyces pombe. The substrate employed was propranolol because it is well metabolized by CYP2D6. Moreover, the CYP2D6 metabolite 4-hydroxypropranolol is a known substrate for the four UGTs included in this study. Co-expression of either UGT1A7, UGT1A8, or UGT1A9 was found to increase the activity of CYP2D6 by a factor of 3.3, 2.1 or 2.8, respectively, for the conversion of propranolol to 4-hydroxypropranolol. In contrast, UGT2A1 co-expression did not change CYP2D6 activity. On the other hand, the activities of all four UGTs were completely suppressed by co-expression of CYP2D6. This data corroborates our previous report that CYP2D6 is involved in functional CYP-UGT interactions and suggest that such interactions can contribute to both adverse drug reactions and changes in drug efficacy.

Effect of Valproate Monotherapy on Thyroid Function Tests and Magnesium Levels in Children With Epilepsy.

BACKGROUND: Antiseizure drug valproate alters thyroid functions. Magnesium is implicated in the pathogenesis of epilepsy and it may affect the efficacy of valproate and thyroid functions. OBJECTIVE: To study the effect of six months of valproate monotherapy on thyroid functions and serum magnesium levels. To study the association among these levels and the effects of clinicodemographic profile. MATERIALS AND METHOD: Children aged three to 12 years presenting with newly diagnosed epilepsy were enrolled. A venous blood sample was collected for estimation of thyroid function test (TFT), magnesium, and valproate levels at onset and after six months of valproate monotherapy. Valproate levels and TFT were analyzed by chemiluminescence and magnesium by colorimetric method. RESULTS: Thyroid stimulating hormone (TSH) increased significantly from 2.14±1.64 µIU/ml at enrollment to 3.64±2.15 µIU/ml at six months (p<0.001), free thyroxine (FT4) decreased significantly (p<0.001). Serum magnesium (Mg) decreased from 2.30±0.29 mg/dl to 1.94±0.28 mg/dl (p<0.001). At six months, eight out of 45 (17.77%) participants had significantly increased mean TSH levels (p=0.008). Serum valproate levels were not associated significantly with TFT and Mg (p<0.05). There was no effect of age, sex, or repeat seizures on the measured parameters. CONCLUSION: The TFT and Mg levels are altered by six months of valproate monotherapy in children with epilepsy. Hence we suggest monitoring and supplementation if required.

Therapeutic Response to Sublingual Methylcobalamin in Children With Vitamin B12 Deficiency Anemia.

OBJECTIVE: To evaluate the efficacy and safety of sublingual methylcobalamin for the treatment of vitamin B12 deficiency anemia in children. METHODS: A single arm intervention study was conducted between November, 2020 and April, 2022 in children aged 1-12 years with vitamin B12 deficiency anemia. Children aged 1-6 years received a tablet of methylcobalamin (1500 mcg) by sublingual route every alternate day (three doses) while those aged 7-12 years received five such doses. Thereafter, one such sublingual tablet was given weekly and all participants were followed-up for 6 weeks. RESULTS: 37 children with a mean (SD) age of 8.2 (4.1) years were treated and followed up prospectively. On day 10, no child needed rescue therapy with parenteral methylcobalamin. After 6 weeks, the mean (SD) serum cobalamin (mL) increased from 123.3 (35.5) pg/mL to 507.3 (274.2) pg/mL (P<0.001), plasma homocysteine (L) decreased from 48.9 (17.8) pg/mL to 16.3 (8.5) µmol/L (P<0.001), the mean (SD) hemoglobin increased by 2.3 (1.1) g/dL (P<0.001), and MCV decreased by 12.9 (6.8) fL (P<0.001). 67.6% children persisted to have anemia, albeit majority of them had mild or moderate anemia. There were no unsolicited side-effect reported. CONCLUSION: Sublingual methylcobalamin is effective for the treatment of vitamin B12 deficiency anemia in children; although, the duration of treatment needs to be longer than six weeks.