Release Kinetics of Potassium, Calcium, and Iron Cations from Carboxymethyl Cellulose Hydrogels at Different pH Values.

In an in-depth study of the mechanism of cation release from carboxymethyl cellulose hydrogels synthesized through Schiff base reaction, we analyze the differences in the release kinetics of potassium, calcium, and iron cations with Peleg model at pH values of pH 3.5 and pH 8.5 using ICP-OES (inductively coupled plasma optical emission spectroscopy) technique.

Pandora cacopsyllae Eilenberg, Keller & Humber (Entomophthorales: Entomophthoraceae), a new species infecting pear psyllid Cacopsylla pyri L. (Hemiptera: Psyllidae).

The new species Pandora cacopsyllae Eilenberg, Keller & Humber (Entomophthorales) is described. The fungus was found on infected pear psyllids Cacopsylla pyri (Hemiptera: Psyllidae) in a pear orchard in Zealand, Denmark. Morphological structures (conidia, rhizoids, cystidia) were described on the designated type host C. pyri. In addition, conidia from an in vitro culture were described. Pandora cacopsyllae differs from other Pandora species by a) C. pyri is the natural host; b) conidia are different from other Pandora species infecting Psylloidea; c) ITS differs from other Pandora species infecting Hemiptera. The fungus has a high potential for future use in biological control of Cacopsylla pest species as well as other psyllids.

Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH): Prevalence, clinicopathological characteristics and survival outcome in a cohort of 311 patients with well-differentiated lung neuroendocrine tumours.

INTRODUCTION: Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is considered to be a rare condition associated with lung neuroendocrine tumours (NET), and its natural history is poorly described. We aimed to assess the prevalence and clinicopathologic characteristics of DIPNECH in the lung NET population, and to investigate predictors of time-to-progression (TTP) and overall survival (OS). METHODS: We retrospectively identified patients diagnosed with DIPNECH between April 2005 and December 2020. Clinical data were collected from medical records. The relationship between baseline characteristics and TTP and OS was analysed using the Kaplan-Meier method. Univariate analysis was performed using the Cox proportional hazards model. RESULTS: Of 311 patients with well-differentiated lung NETs, 61 (20%) had DIPNECH and were included in the study. Baseline demographics described 95% female, 59% never smokers and mean body mass index 34.4 kg m-2 ; 77% were typical carcinoids (TC), 13% atypical carcinoids (AC), and 10% both TC and AC (multicentric). At presentation, 54% of patients were asymptomatic. Multicentric NETs were demonstrated in 16 (26%) on histopathology, and a further 32 (52%) had synchronous NETs suggested on imaging (multiple nodules ≥ 5 mm). Seven (11%) patients developed metastases and the median OS from time of first metastasis was 37 months. AC histopathology and NET TNM stage ≥ IIA were associated with poorer TTP and OS. Of the DIPNECH cohort, the 15-year survival rate was 86%. CONCLUSIONS: DIPNECH may be more prevalent in the lung NET population than previously appreciated, especially in women. Although our results confirm that DIPNECH is predominantly an indolent disease associated with TC, 23% developed AC and these patients may warrant closer observation.

Impact of society and national guidelines on patient selection for lung cancer surgery in the United Kingdom.

OBJECTIVES: We sought to evaluate the impact of different national clinical guidelines (with consistent and conflicting recommendations) on clinician's practice in the UK. METHODS: In this cohort study, we analysed data from National Lung Cancer Audit comprising all patients diagnosed with lung cancer between 2008 and 2013 within England and Wales for consistent (British Thoracic Society and National Institute of Clinical Excellence) recommendations for lower/more permissive lung function but opposing stage (N2) selection parameters for surgery. RESULTS: From 2008 to 2013, data from 167 192 patients with primary lung cancers were included. The proportion of patients undergoing surgery for lung cancer increased from 9.5% to 20.5% in 2013 (P < 0.001) as the number of general thoracic surgeons in the UK increased from 40 to 81 in the corresponding timeframe. Mean forced expiratory volume in 1 s of surgical patients increased from 76% (22) to 81% (22) in 2013 (P < 0.001). Of the patients undergoing surgery, the proportion of patients with N2 disease across the 6-year interval was broadly consistent between 8% and 11% without any evidence of trend (P = 0.125). CONCLUSIONS: Within 3 years of new clinical guideline recommendations, we did not observe any overall change suggesting greater selection for surgery on lower levels of lung function. When presented with conflicting recommendation, no observable change in selection was noted on surgery for N2 disease. The observed increase in surgical resection rates is more likely due to greater access to surgery (by increasing number of surgeons) rather than any impact of guideline recommendations.

Elective ENT surgery during the COVID-19 pandemic: Experience from a single UK centre.

AIM: To analyse the outcomes of patients who underwent elective ENT surgery during the first peak of the COVID-19 pandemic in a COVID free site. METHODS: This is a retrospective single centre case series of all patients undergoing elective ENT surgery over a 16-week period between 1 April and 22 July 2020. RESULTS: No patients, out of our cohort of 85, developed postoperative COVID-19 symptoms or complications of COVID-19. There were no mortalities. CONCLUSION: The results suggests that hospitals can safely manage elective ENT operating services during the pandemic.

Inadvertent intrathecal administration of daunomycin resulting in fatality: Case report and therapeutic considerations.

BACKGROUND: Daunomycin is a chemotherapeutic agent of the anthracycline family that is administered intravenously, most commonly in combination therapy. The authors report the first known adult case of inadvertently administered daunomycin directly into the human central nervous system and the neurologic manifestations and therapeutic interventions that followed. CLINICAL DESCRIPTION: A 53-year-old male presenting to the hospital for his second cycle of consolidation therapy for acute promyelocytic leukemia t(15;17) was accidentally administered 93 mg of intrathecal (IT) daunomycin. Within several hours of injection, the patient subsequently developed bilateral lower extremity pain, ascending paresthesias, headache, and left cranial nerve (CN) III palsy. Immediately following these neurologic sequalae, a subarachnoid lumbar drain was placed at the L4-5 interspace for the initial irrigation and drainage of cerebrospinal fluid (CSF). By hospital day 2, the patient's mental status significantly declined requiring an external ventricular drain (EVD) for hydrocephalus. Despite therapeutic interventions, the patient developed an ascending radiculomyeloencephalopathy with deterioration in clinical status. Eighteen days after the inadvertent injection of IT daunomycin, the patient became comatose and lost all cranial nerve function. CONCLUSIONS: Accidental IT injection of daunomycin is a neurosurgical emergency and warrants prompt intervention. Symptoms can mimic other medical conditions, making it imperative an accurate diagnosis is made so that appropriate therapies are implemented. At this time, therapies include rapid removal of the chemotherapeutic agent from the IT compartment by aspiration and irrigation; however, it is unclear if neuroprotective agents may provide added benefit.

Energetics of Excitatory and Inhibitory Neurotransmission in Aluminum Chloride Model of Alzheimer's Disease: Reversal of Behavioral and Metabolic Deficits by Rasa Sindoor.

Alzheimer's disease (AD) is an age-related neurodegenerative disorder, characterized by progressive loss of cognitive functions and memory. Excessive intake of aluminum chloride in drinking water is associated with amyloid plaques and neurofibrillary tangles in the brain, which are the hallmark of AD. We have evaluated brain energy metabolism in aluminum chloride (AlCl3) mouse model of AD. In addition, effectiveness of Rasa Sindoor (RS), a formulation used in Indian Ayurvedic medicine, for alleviation of symptoms of AD was evaluated. Mice were administered AlCl3 (40 mg/kg) intraperitoneally once a day for 60 days. The memory of mice was measured using Morris Water Maze test. The 13C labeling of brain amino acids was measured ex vivo in tissue extracts using 1H-[13C]-NMR spectroscopy with timed infusion of [1,6-13C2]glucose. The 13C turnover of brain amino acids was analyzed using a three-compartment metabolic model to derive the neurotransmitter cycling and TCA cycle rates associated with glutamatergic and GABAergic pathways. Exposure of AlCl3 led to reduction in memory of mice. The glutamatergic and GABAergic neurotransmitter cycling and glucose oxidation were found to be reduced in the cerebral cortex, hippocampus, and striatum following chronic AlCl3 treatment. The perturbation in metabolic rates was highest in the cerebral cortex. However, reduction in metabolic fluxes was higher in hippocampus and striatum following one month post AlCl3 treatment. Most interestingly, oral administration of RS (2 g/kg) restored memory as well as the energetics of neurotransmission in mice exposed to AlCl3. These data suggest therapeutic potential of RS to manage cognitive functions and memory in preclinical AD.

Assessment of nodal involvement in non-small-cell lung cancer with 18F-FDG-PET/CT: mediastinal blood pool cut-off has the highest sensitivity and tumour SUVmax/2 has the highest specificity.

OBJECTIVES: Lymph node involvement in non-small-cell lung cancer (NSCLC) is a major factor in determining management and prognosis. We aimed to evaluate the accuracy of fluorine-18-fluorodeoxyglucose-PET/computed tomography (CT) for the assessment of nodal involvement in patients with NSCLC. PATIENTS AND METHODS: In this retrospective study, we included 61 patients with suspected or confirmed resectable NSCLC over a 2-year period from April 2013 to April 2015. 221 nodes with pathological staging from surgery or endobronchial ultrasound-guided transbronchial needle aspiration were assessed using a nodal station-based analysis with original clinical reports and three different cut-offs: mediastinal blood pool (MBP), liver background and tumour standardized uptake value maximal (SUVmax)/2. RESULTS: Using nodal station-based analysis for activity more than tumour SUVmax/2, the sensitivity was 45%, the specificity was 89% and the negative predictive value (NPV) was 87%. For activity more than MBP, the sensitivity was 93%, the specificity was 72% and NPV was 98%. For activity more than liver background, the sensitivity was 83%, the specificity was 84% and NPV was 96%. Using a nodal staging-based analysis for accuracy at detecting N2/3 disease, for activity more than tumour SUVmax/2, the sensitivity was 59%, the specificity was 85% and NPV was 80%. For activity more than MBP, the sensitivity was 95%, the specificity was 61% and NPV was 96%. For activity more than liver background, the sensitivity was 86%, the specificity was 81% and NPV was 92%. Receiver-operating characteristic analysis showed the optimal nodal SUVmax to be more than 6.4 with a sensitivity of 45% and a specificity of 95%, with an area under the curve of 0.85. CONCLUSION: Activity more than MBP was the most sensitive cut-off with the highest sensitivity and NPV. Activity more than primary tumour SUVmax/2 was the most specific cut-off. Nodal SUVmax more than 6.4 has a high specificity of 95%.

Direct one-pot synthesis of glutathione capped hydrophilic FePt-CdS nanoprobe for efficient bimodal imaging application.

One-pot synthesis methods for development of hydrophilic imaging nanoprobes have advantages over multi-pot methods due to their simple procedures, less probability for degradation of efficiency, superior control over growth and morphology, cost effectiveness, improved scope for scale-up synthesis etc. Here, we present a novel one-pot facile synthesis of hydrophilic colloidal bimodal nanoprobe (FePt-CdS) prepared through a seed-mediated nucleation and growth technique. In this facile synthesis of complex nanostructure, glutathione (GSH) was used as the capping agent to render biocompatibility and dispersibility. The microstructure, surface, optical, magnetic, biocompatibility, relaxivity and imaging property of the developed nanoprobe have been studied. The microstructural characterizations reveal average size of the particle as ~9-11nm with bleb shaped morphology. Spectroscopic characterization depicts the development of GSH capped CdS QDs on FePt, surface functionalities and their stability. The magnetic measurements confirm the superparamagnetic property in the developed bimodal nanoprobe. In addition, the GSH capping imparts excellent biocompatibility, water dispersibility, and fluorescence property to the probe. In RAW 264.7 macrophage cells, the bimodal nanoprobes exhibit intense green and red fluorescence. The magnetic resonance imaging (MRI) and fluorescence imaging (FI) study depict high transverse relaxivity and visible range fluorescent property in the synthesized FePt-CdS nanoprobe. Hence, the developed bimodal nanoprobe can be used as a potential candidate in simultaneous FI and MR imaging.

A designed recombinant fusion protein for targeted delivery of siRNA to the mouse brain.

RNA interference represents a novel therapeutic approach to modulate several neurodegenerative disease-related genes. However, exogenous delivery of siRNA restricts their transport into different tissues and specifically into the brain mainly due to its large size and the presence of the blood-brain barrier (BBB). To overcome these challenges, we developed here a strategy wherein a peptide known to target specific gangliosides was fused to a double-stranded RNA binding protein to deliver siRNA to the brain parenchyma. The designed fusion protein designated as TARBP-BTP consists of a double-stranded RNA-binding domain (dsRBD) of human Trans Activation response element (TAR) RNA Binding Protein (TARBP2) fused to a brain targeting peptide that binds to monosialoganglioside GM1. Conformation-specific binding of TARBP2 domain to siRNA led to the formation of homogenous serum-stable complex with targeting potential. Further, uptake of the complex in Neuro-2a, IMR32 and HepG2 cells analyzed by confocal microscopy and fluorescence activated cell sorting, revealed selective requirement of GM1 for entry. Remarkably, systemic delivery of the fluorescently labeled complex (TARBP-BTP:siRNA) in ΑßPP-PS1 mouse model of Alzheimer's disease (AD) led to distinctive localization in the cerebral hemisphere. Further, the delivery of siRNA mediated by TARBP-BTP led to significant knockdown of BACE1 in the brain, in both ΑßPP-PS1 mice and wild type C57BL/6. The study establishes the growing importance of fusion proteins in delivering therapeutic siRNA to brain tissues.

Conservative or radical surgery for pediatric papillary thyroid carcinoma: A systematic review of the literature.

BACKGROUND: Pediatric papillary thyroid carcinoma (PTC) is characterized by an aggressive clinical course. Early diagnosis is a challenge and treatment consists principally of partial or total thyroidectomy±neck dissection and radioactive iodine therapy. Due to the rarity of PTC in children, there is no consensus on optimal surgical treatment. METHODS AND RESULTS: A literature search was carried out using PubMed, Embase, Medline, Cochrane and Web of Science. Seven studies (489 patients) investigating the outcome of surgically managed pediatric PTC were identified. No clear advantage in survival or recurrence rate was found for total thyroidectomy compared to other surgical approaches. CONCLUSION: Despite the aggressive behavior of PTC, prognosis is good, with low mortality. After removal of disease and prevention of recurrence, reduction of iatrogenic complications are a priority in this age group. Due to the paucity of available evidence, this review cannot recommend conservative or radical surgery for pediatric papillary thyroid carcinoma. To answer this question, we recommend the establishment of a randomized controlled trial with adequately matched baseline variables.

Lung function, symptoms and inflammation during exacerbations of non-cystic fibrosis bronchiectasis: a prospective observational cohort study.

BACKGROUND: Exacerbations of non-cystic fibrosis bronchiectasis cause significant morbidity but there are few detailed data on their clinical course and associated physiological changes. The biology of an exacerbation has not been previously described. METHODS: This was a prospective observational cohort study of 32 outpatients with non-cystic fibrosis bronchiectasis conducted between August 2010 and August 2012. Patients completed a symptom diary card and measured their peak expiratory flow rate (PEFR) daily. Exacerbations were defined as oral antibiotic treatment taken for a worsening of respiratory symptoms. Symptoms and peak flow at exacerbation were analysed, and further measurements including the COPD Assessment Test (CAT) and inflammatory markers were also compared to baseline values. RESULTS: At baseline, health status was significantly related to lung function, prognostic severity and systemic inflammation. 51 exacerbations occurred in 22 patients. Exacerbation symptoms began a median (interquartile range) of 4 (2, 7) days before treatment started and the median exacerbation duration was 16 (10, 29) days. 16% had not recovered by 35 days. At exacerbation, mean PEFR dropped by 10.6% (95% confidence interval 6.9-14.2, p < 0.001) and mean CAT score increased by 6.3 units (3.6-9.1, p = 0.001), median symptom count by 4 (2.25, 6, p < 0.001), and mean CRP by 9.0mg/L (2.3-15.8, p = 0.011). Exacerbations where PEFR fell by ≥10% were longer with more symptoms at onset. CONCLUSION: Exacerbations of non-CF bronchiectasis are inflammatory events, with worsened symptoms, lung function and health status, and a prolonged recovery period. Symptom diary cards, PEFR and CAT scores are responsive to changes at exacerbation and may be useful tools for their detection and monitoring.

RNA Interference Using c-Myc-Conjugated Nanoparticles Suppresses Breast and Colorectal Cancer Models.

In this article, we report the development and preclinical validation of combinatorial therapy for treatment of cancers using RNA interference (RNAi). RNAi technology is an attractive approach to silence genes responsible for disease onset and progression. Currently, the critical challenge facing the clinical success of RNAi technology is in the difficulty of delivery of RNAi inducers, due to low transfection efficiency, difficulties of integration into host DNA and unstable expression. Using the macromolecule polyglycidal methacrylate (PGMA) as a platform to graft multiple polyethyleneimine (PEI) chains, we demonstrate effective delivery of small oligos (anti-miRs and mimics) and larger DNAs (encoding shRNAs) in a wide variety of cancer cell lines by successful silencing/activation of their respective target genes. Furthermore, the effectiveness of this therapy was validated for in vivo tumor suppression using two transgenic mouse models; first, tumor growth arrest and increased animal survival was seen in mice bearing Brca2/p53-mutant mammary tumors following daily intratumoral treatment with nanoparticles conjugated to c-Myc shRNA. Second, oral delivery of the conjugate to an Apc-deficient crypt progenitor colon cancer model increased animal survival and returned intestinal tissue to a non-wnt-deregulated state. This study demonstrates, through careful design of nonviral nanoparticles and appropriate selection of therapeutic gene targets, that RNAi technology can be made an affordable and amenable therapy for cancer.

Human rhinovirus infection during naturally occurring COPD exacerbations.

Human rhinovirus (HRV) infection is an important trigger of exacerbations of chronic obstructive pulmonary disease (COPD) but its role in determining exacerbation frequency phenotype or the time-course of HRV infection in naturally occurring exacerbations is unknown. Sputum samples from 77 patients were analysed by real-time quantitative PCR for both HRV (388 samples), and Streptococcus pneumoniae, Haemophilus influenzae and Moraxella catarrhalis (89 samples). Patients recorded worsening of respiratory symptoms on daily diary cards, from which exacerbations were identified. HRV prevalence and load at exacerbation presentation were significantly higher than in the stable state (prevalence 53.3% versus 17.2%, respectively; p<0.001) but 0% by day 35 post-exacerbation. HRV load was higher in patients with cold symptoms (p=0.046) or sore throats (p=0.006) than those without. 73% of bacterium-negative but HRV-positive exacerbations were bacterium-positive by day 14. Patients with HRV detected at exacerbation had a higher exacerbation frequency (interquartile range) of 3.01 (2.02-5.30) per year compared with patients without HRV (2.51 (2.00-3.51)) (p=0.038). HRV prevalence and load increased at COPD exacerbation, and resolved during recovery. Frequent exacerbators were more likely to experience HRV infection. Secondary bacterial infection is common after HRV infection, and provides a possible mechanism for exacerbation recurrence and a potential target for novel therapies.

Antiangiogenic therapy inhibits venous thrombus resolution.

OBJECTIVE: Venous thromboembolism is a common complication in patients with cancer, resulting in significant morbidity and mortality. Clinical studies suggest that the incidence of venous thromboembolic events increased after treatment of these patients with antiangiogenic agents. Thrombi resolve through a process of remodeling, involving the formation of microvascular channels within the thrombus. Our aim was to determine whether inhibiting angiogenesis affects venous thrombus resolution. APPROACH AND RESULTS: Thrombus was induced in the inferior vena cava of mice. These mice were treated with axitinib (50 mg/kg per day), 2-methoxyestradiol (2ME, 150 mg/kg per day), or vehicle control. Thrombus size, recanalization, neovascularization, inflammatory cell content, and collagen content were assessed after axitinib (days 3, 10, 17) and 2ME (day 10 only) treatment (n=6/group). Axitinib treatment resulted in reduced thrombus resolution (P<0.002) and vein recanalization (P<0.001) compared with vehicle-treated controls. This was associated with inhibition of organization as seen through reduced thrombus neovascularization (P<0.0001) and collagen (P<0.0001) content, as well as reduced macrophage accumulation in the thrombus (P<0.001). Treatment with a second antiangiogenic agent, 2ME, mirrored these findings, with a similar order of magnitude of effect of treatment over vehicle control in all of the parameters measured, with the exception of neutrophil content, which was significantly reduced after 2ME treatment but not affected by axitinib. CONCLUSIONS: Antiangiogenic therapy (using axitinib and 2ME) inhibits the resolution of venous thrombi, which could lead to persistent venous obstruction and the possibility of thrombus extension. This potential prolongation of venous occlusion by antiangiogenic agents should therefore be taken into consideration in trials of these agents and when managing the complications of venous thromboembolic events in patients with cancer.

Cardiovascular risk, myocardial injury, and exacerbations of chronic obstructive pulmonary disease.

RATIONALE: Patients with chronic obstructive pulmonary disease (COPD) have elevated cardiovascular risk, and myocardial injury is common during severe exacerbations. Little is known about the prevalence, magnitude, and underlying mechanisms of cardiovascular risk in community-treated exacerbations. OBJECTIVES: To investigate how COPD exacerbations and exacerbation frequency impact cardiovascular risk and myocardial injury, and whether this is related to airway infection and inflammation. METHODS: We prospectively measured arterial stiffness (aortic pulse wave velocity [aPWV]) and cardiac biomarkers in 98 patients with stable COPD. Fifty-five patients had paired stable and exacerbation assessments, repeated at Days 3, 7, 14, and 35 during recovery. Airway infection was identified using polymerase chain reaction. MEASUREMENTS AND MAIN RESULTS: COPD exacerbation frequency was related to stable-state arterial stiffness (rho = 0.209; P = 0.040). Frequent exacerbators had greater aPWV than infrequent exacerbators (mean ± SD aPWV, 11.4 ± 2.1 vs. 10.3 ± 2.0 ms(-1); P = 0.025). Arterial stiffness rose by an average of 1.2 ms(-1) (11.1%) from stable state to exacerbation (n = 55) and fell slowly during recovery. In those with airway infection at exacerbation (n = 24) this rise was greater (1.4 ± 1.6 vs. 0.7 ± 1.3 ms(-1); P = 0.048); prolonged; and related to sputum IL-6 (rho = 0.753; P < 0.001). Increases in cardiac biomarkers at exacerbation were higher in those with ischemic heart disease (n = 12) than those without (n = 43) (mean ± SD increase in troponin T, 0.011 ± 0.009 vs. 0.003 ± 0.006 µg/L, P = 0.003; N-terminal pro-brain natriuretic peptide, 38.1 ± 37.7 vs. 5.9 ± 12.3 pg/ml, P < 0.001). CONCLUSIONS: Frequent COPD exacerbators have greater arterial stiffness than infrequent exacerbators. Arterial stiffness rises acutely during COPD exacerbations, particularly with airway infection. Increases in arterial stiffness are related to inflammation, and are slow to recover. Myocardial injury is common and clinically significant during COPD exacerbations, particularly in those with underlying ischemic heart disease.

Gene delivery into human cancer cells by cationic lipid-mediated magnetofection.

In this study, a combination of magnetic nanoparticles (MNPs) together with cationic lipid N,N-di-n-hexadecyl-N,N-dihydroxyethylammonium chloride formulated with colipid cholesterol, upon magnetofection, enhanced DNA uptake into human glioblastoma-astrocytoma, epithelial-like cell line U-87 MG, hepatocellular carcinoma Hep G2, cervical cancer HeLa and breast cancer MDA-MB-231 cells. Having confirmed this, we monitored uptake of plasmid DNA mediated by ternary magnetoplexes by fluorescence microscopy, flow cytometry and reporter gene expression assays in the presence and absence of a magnetic field. Our observations clearly indicate enhanced transfection efficiency in vitro, upon magnetofection, in the presence of serum as seen from ß-Gal reporter gene expression. The observed activity in serum suggests the suitability of MNPs for in vivo applications. Further, we measured the transverse relaxation time (T2) and obtained T2-weighted MRI images of treated U-87 MG cells. T2 determined for MNP-VP-Me22 and MNP-VP-Et22 corresponds to 22.6±0.8 ms and 36.0±2.1 ms, respectively, as compared to 47±1.7 ms for control, suggesting their applicability in molecular imaging. Our results collectively highlight the potential of lipid-based approach to augment magnetic-field guided-gene delivery using MNPs and additionally towards developing intracellular molecular probes for magnetic resonance imaging.

Glutamatergic and GABAergic metabolism in mouse brain under chronic nicotine exposure: implications for addiction.

BACKGROUND AND PURPOSE: The effects of nicotine on cerebral metabolism and its influence on smoking behavior is poorly understood. An understanding of the chronic effects of nicotine on excitatory and inhibitory metabolic demand, and corresponding neurotransmission may provide clues for designing strategies for the optimal smoking cessation intervention. The objective of the current study was to investigate neuronal and astroglial metabolism in mice exposed to nicotine (0.5 and 2.0 mg/kg, s.c.) three times in a day for 4 weeks. EXPERIMENTAL APPROACH/PRINCIPAL FINDINGS: Metabolic measurements were carried out by co-infusing [U-(13)C(6)]glucose and [2-(13)C]acetate, and monitoring (13)C labeling of amino acids in brain tissue extract using (1)H-[(13)C] and (13)C-[(1)H]-NMR spectroscopy. Concentration of (13)C-labeled glutamate-C4 was increased significantly from glucose and acetate with chronic nicotine treatment indicating an increase in glucose oxidation by glutamatergic neurons in all brain regions and glutamate-glutamine neurotransmitter cycle in cortical and subcortical regions. However, chronic nicotine treatment led to increased labeling of GABA-C2 from glucose only in the cortical region. Further, increased labeling of glutamine-C4 from [2-(13)C]acetate is suggestive of increased astroglial activity in subcortical and cerebellum regions of brain with chronic nicotine treatment. CONCLUSIONS AND SIGNIFICANCE: Chronic nicotine exposure enhanced excitatory activity in the majority of brain regions while inhibitory and astroglial functions were enhanced only in selected brain regions.