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2.
Nanomaterials (Basel) ; 13(5)2023 Feb 22.
Article in English | MEDLINE | ID: mdl-36903687

ABSTRACT

A radiator is used to remove a portion of the heat generated by a vehicle engine. It is challenging to efficiently maintain the heat transfer in an automotive cooling system even though both internal and external systems need enough time to keep pace with catching up with evolving engine technology advancements. The effectiveness of a unique hybrid's heat transfer nanofluid was investigated in this study. The hybrid nanofluid was mainly composed of graphene nanoplatelets (GnP), and cellulose nanocrystals (CNC) nanoparticles suspended in a 40:60 ratio of distilled water and ethylene glycol. A counterflow radiator equipped with a test rig setup was used to evaluate the hybrid nano fluid's thermal performance. According to the findings, the proposed GNP/CNC hybrid nanofluid performs better in relation to improving the efficiency of heat transfer of a vehicle radiator. The suggested hybrid nanofluid enhanced convective heat transfer coefficient by 51.91%, overall heat transfer coefficient by 46.72%, and pressure drop by 34.06% with respect to distilled water base fluid. Additionally, the radiator could reach a better CHTC with 0.01% hybrid nanofluid in the optimized radiator tube by the size reduction assessment using computational fluid analysis. In addition to downsizing the radiator tube and increasing cooling capacity over typical coolants, the radiator takes up less space and helps to lower the weight of a vehicle engine. As a result, the suggested unique hybrid graphene nanoplatelets/cellulose nanocrystal-based nanofluids perform better in heat transfer enhancement in automobiles.

3.
Appl Biochem Biotechnol ; 195(7): 4570-4582, 2023 Jul.
Article in English | MEDLINE | ID: mdl-36705843

ABSTRACT

The objective of this study was to evaluate phytochemicals present in the resin of Garcinia indica (Gamboge). We assessed the phytochemical constituents and antioxidant potential of acetone, methanol, and water extracts of resin. Acetone and methanol extracts contain a high amount of phenolics (183.90 and 182.85 mg GAE (gallic acid equivalent)/g) and flavonoids (72.65 and 71.33 mg QE (quercetin equivalent)/g), respectively, whereas methanol extract had the highest 7.62 mg AE (atropine equivalent)/g of alkaloid. GC-MS analysis of acetone extract identified 15 compounds and the majority of them were terpenoids, and 9,19-cyclo-25,26-epoxyergostan-3-ol,4,4,14-trimethyl-, acetate was the major compound among all terpenoids. Both acetone and methanol extracts showed excellent antioxidant activity as assessed by DPPH, total antioxidant activity, and FRAP assays. This experimental evidence suggests that G. indica resin is an excellent source of bioactive compounds and can be explored for its medicinal applications.


Subject(s)
Antioxidants , Garcinia , Antioxidants/chemistry , Plant Extracts/chemistry , Methanol , Gas Chromatography-Mass Spectrometry , Acetone/analysis , Phytochemicals/chemistry
4.
Br J Neurosurg ; 36(1): 90-93, 2022 Feb.
Article in English | MEDLINE | ID: mdl-29745267

ABSTRACT

Pilocytic astrocytoma is a benign low-grade tumor with a favorable prognosis. We present a 47-year-old- lady with a posterior fossa pilocytic astrocytoma who underwent surgical decompression. She developed multiple early local recurrences Along with malignant transformation of the cranial lesion she developed skeletal dissemination within a very short time frame. There were no features or family history of neurofibromatosis 1. She did not receive radiotherapy or chemotherapy prior to the recurrences.


Subject(s)
Astrocytoma , Neurofibromatosis 1 , Astrocytoma/diagnostic imaging , Astrocytoma/pathology , Astrocytoma/surgery , Cell Transformation, Neoplastic/pathology , Decompression, Surgical , Female , Humans , Middle Aged , Neurofibromatosis 1/surgery , Recurrence
5.
J Med Syst ; 43(8): 257, 2019 Jul 01.
Article in English | MEDLINE | ID: mdl-31264006

ABSTRACT

Telemedicine research improves the connectivity of remote patients and doctors. Researchers are focused on data optimization and processing over a predefined channel of communication under a depictive low QoS. In this paper a consolidated representation of telemedicine infrastructure of modern topological arrangement is represented and validated. The infrastructure is aided with Multiple Objective Optimized Medical dataset (MooM) processing and a channel optimizing TelMED protocol designed exclusively for remote medicine dataset transmission and processing. The proposed infrastructure provides an application oriented approach towards Electronics health records (EHR) creation and updating over edge computation. The focus of this article is to achieve higher order of Quality of Service (QoS) and Quality of Data (QoD) compared to typical communication channels algorithms for processing of medical data sample. Typically the proposed technique results are achieved to discuss in MooM dataset processing and TelMED channel optimization sessions and a resulting improvement is discussed with a comparison of each MooM dataset in reverse processing towards server end of diagnosis and a consolidated QoS is retrieved for proposed infrastructure.


Subject(s)
Datasets as Topic , Electronic Data Processing , Quality of Health Care , Remote Consultation , Telemedicine , Wireless Technology , Signal Processing, Computer-Assisted
6.
Indian J Sex Transm Dis AIDS ; 40(1): 64-66, 2019.
Article in English | MEDLINE | ID: mdl-31143863

ABSTRACT

Although HIV infection can mimic the manifestations of various autoimmune disorders, the coexistence of HIV and systemic lupus erythematosus (SLE) has been rarely reported. The exact impact of HIV on SLE and vice versa is unclear. We report an HIV-seropositive female on highly active antiretroviral therapy presenting with features of SLE. Herein, an attempt has been made to discuss the various complex clinical and therapeutic implications along with the influence on disease course and prognosis.

7.
J Clin Neurosci ; 42: 97-101, 2017 Aug.
Article in English | MEDLINE | ID: mdl-28457859

ABSTRACT

OBJECTIVES: To find the correlation between radiologically proven improvement in cerebral hemodynamics with clinical improvement in patients undergoing cranioplasty. MATERIAL AND METHODS: The study is a prospective observational study of 10 cases, in M S Ramaiah Institute of Neurosciences, involving patients treated by a decompressive craniectomy for intractable intra cranial hypertension either due to trauma or stroke and afterwards underwent cranioplasty. RESULTS: Of the 10 patients, 70% patients showing significant improvement in motor functions on Barthel index scale, 60% patients showed improvement in speech, mean duration from date of decompressive craniectomy to cranioplasty being 122.4days. Cerebral perfusion was remarkably better after cranioplasty, as demonstrated decrease in the Pulsatility index on the ipsilateral side of decompression on Trans cranial Doppler (<0.73 mean). This data also favored improved cerebral blood flow and permeability on the CT perfusion with increase in cerebral blood flow (CBF), Cerebral Blood Volume (CBV) and decrease in Time to Peak (TTP) and a positive outcome when correlated with Barthel index with P-values of 0.093, 0.017 and 0.001 respectively. CONCLUSION: Cranioplasty influences the cerebral hemodynamics after cranioplasty and has a positive correlation on the functional outcome and cerebral blood flow in the MCA territory.


Subject(s)
Bone Transplantation/adverse effects , Decompressive Craniectomy , Hemodynamics/physiology , Intracranial Hypertension/physiopathology , Intracranial Hypertension/surgery , Plastic Surgery Procedures/adverse effects , Skull/surgery , Cerebrovascular Circulation/physiology , Female , Humans , Intracranial Hypertension/diagnostic imaging , Male , Prospective Studies , Treatment Outcome
8.
Neurol India ; 64(4): 633-9, 2016.
Article in English | MEDLINE | ID: mdl-27381106

ABSTRACT

OBJECTIVES: To compare the clinical, balance, and radiological profile of progressive supranuclear palsy (PSP) of Richardson type (PSP-R) and Parkinsonian type (PSP-P). MATERIALS AND METHODS: Twenty-nine patients with PSP (PSP-R: 17, PSP-P: 12) satisfying the probable/possible National Institute of Neurological Disorders and Stroke-PSP criteria were recruited and assessed with Unified Parkinson's Disease Rating Scale-III, PSP rating scale (PSPRS), Berg balance scale (BBS), Tinetti performance-oriented mobility assessment gait and total (TPG and TPT) score, dynamic posturography (DP), and magnetic resonance imaging. Data were compared with 30 age- and gender-matched healthy controls. RESULTS: The mean ages of PSP-R, PSP-P, and controls were comparable (62.5 ± 6.6, 59 ± 8.9, and 59.8 ± 7.6 years). The PSP group had significantly poor DP scores and more radiological abnormalities than controls. The PSPRS, TPG, and TPT scores were significantly more impaired in PSP-R compared to PSP-P (P = 0.045, P = 0.031, and P = 0.037, respectively). In DP, the limits of overall stability were most significant (P < 0.001) and PSP-R had lower scores. PSP-R compared to PSP-P had more often "Humming Bird" sign (P < 0.001), "Morning Glory" sign (P < 0.008), and generalized cortical atrophy (P < 0.001). The area of midbrain (P < 0.002) and midbrain/pons ratio (P < 0.013) was significantly lower in PSP-R. In PSP-P, the overall balance index significantly correlated with BBS, TPG, and TPT (r = -0.79, P = 0.002; r = -0.772, P = 0.003; and r = -0.688, P = 0.013) and the midbrain axial anterior-posterior diameter significantly correlated with the TPG and TPT (r = 0.74, P = 0.01; r = 0.66, P = 0.018). CONCLUSIONS: While balance and radiological abnormalities were more severe in PSP-R, the qualitative and quantitative measurements of severity of balance in PSP-P rather than PSP-R was a better reflection of the pathology of the midbrain.


Subject(s)
Magnetic Resonance Imaging , Mesencephalon/pathology , Supranuclear Palsy, Progressive/diagnostic imaging , Aged , Atrophy , Female , Humans , Male , Mesencephalon/diagnostic imaging , Middle Aged , Supranuclear Palsy, Progressive/pathology
10.
Bioresour Technol ; 164: 170-6, 2014 Jul.
Article in English | MEDLINE | ID: mdl-24859207

ABSTRACT

The feasibility of coupled biohydrogen and polyhydroxyalkanoate production by Enterobacter aerogenes and Rhodobacter sphaeroides using Calophyllum inophyllum oil cake was studied under dark and photo fermentation conditions. The utilization of a non-edible acidic oil cake (C. inophyllum), and exploitation of a modified minimal salt media led to reduction in the cost of media. Cost of fermentation is reduced by implementation of alternate dark-photo fermentative periods and through the use of a co-culture consisting of a dark fermentative (E. aerogenes) and a photo fermentative (R. sphaeroides) bacterium. The biohydrogen and polyhydroxyalkanoate produced were 7.95 L H2/L media and 10.73 g/L media, respectively, under alternate dark and photo fermentation and were 3.23 L H2/L media and 5.6g/L media, respectively under complete dark fermentation. The characteristics of the oil cake and alternate dark (16 h) and photo (8h) fermentative conditions were found to be supportive in producing high biohydrogen and polyhydroxyalkanoate (PHA) yield.


Subject(s)
Biofuels/microbiology , Biotechnology/methods , Calophyllum/metabolism , Enterobacter aerogenes/metabolism , Hydrogen/metabolism , Polyhydroxyalkanoates/biosynthesis , Rhodobacter sphaeroides/metabolism , Calophyllum/radiation effects , Enterobacter aerogenes/growth & development , Enterobacter aerogenes/radiation effects , Fermentation/radiation effects , Light , Plant Oils/metabolism , Proton Magnetic Resonance Spectroscopy , Rhodobacter sphaeroides/growth & development , Rhodobacter sphaeroides/radiation effects , Spectroscopy, Fourier Transform Infrared
11.
Toxicol Sci ; 136(2): 500-13, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24014653

ABSTRACT

Non-dioxin like polychlorinated biphenyls (NDL-PCBs) are legacy environmental contaminants with contemporary unintentional sources. NDL-PCBs interact with ryanodine receptors (RyRs), Ca(2+) channels of sarcoplasmic/endoplasmic reticulum (SR/ER) that regulate excitation-contraction coupling (ECC) and Ca(2+)-dependent cell signaling in muscle. Activities of 4 chiral congeners PCB91, 95, 132, and 149 and their respective 4- and 5-hydroxy (-OH) derivatives toward rabbit skeletal muscle ryanodine receptor (RyR1) are investigated using [(3)H]ryanodine binding and SR Ca(2+) flux analyses. Although 5-OH metabolites have comparable activity to their respective parent in both assays, 4-OH derivatives are unable to trigger Ca(2+) release from SR microsomes in the presence of Ca(2+)-ATPase activity. PCB95 and derivatives are investigated using single channel voltage-clamp and primary murine embryonic muscle cells (myotubes). Like PCB95, 5-OH-PCB95 quickly and persistently increases channel open probability (p o > .9) by stabilizing the full-open channel state, whereas 4-OH-PCB95 transiently enhances p o. Ca(2+) imaging of myotubes loaded with Fluo-4 show that acute exposure to PCB95 (5 µM) potentiates ECC and caffeine responses and partially depletes SR Ca(2+) stores. Exposure to 5-OH-PCB95 (5 µM) increases cytoplasmic Ca(2+), leading to rapid ECC failure in 50% of myotubes with the remainder retaining negligible responses. 4-OH-PCB95 neither increases baseline Ca(2+) nor causes ECC failure but depresses ECC and caffeine responses by 50%. With longer (3h) exposure to 300 nM PCB95, 5-OH-PCB95, or 4-OH-PCB95 decreases the number of ECC responsive myotubes by 22%, 81%, and 51% compared with control by depleting SR Ca(2+) and/or uncoupling ECC. NDL-PCBs and their 5-OH and 4-OH metabolites differentially influence RyR1 channel activity and ECC in embryonic skeletal muscle.


Subject(s)
Muscle, Skeletal/drug effects , Polychlorinated Biphenyls/toxicity , Ryanodine Receptor Calcium Release Channel/metabolism , Animals , Calcium/metabolism , Cells, Cultured , Mice , Mice, Inbred C57BL , Muscle Contraction/drug effects , Muscle, Skeletal/enzymology , Muscle, Skeletal/physiopathology , Polychlorinated Biphenyls/chemistry , Rabbits , Sarcoplasmic Reticulum Calcium-Transporting ATPases/metabolism , Structure-Activity Relationship
12.
Eur J Neurol ; 20(3): 493-501, 2013 Mar.
Article in English | MEDLINE | ID: mdl-23061493

ABSTRACT

BACKGROUND AND PURPOSE: To study the abnormalities of deep grey matter (GM) structures in patients with progressive supranuclear palsy (PSP) using MR volumetry and shape analysis techniques. METHODS: Twenty-eight patients with PSP and 25 matched controls (all were right handed) were evaluated using standard clinical scales. MRI was performed on a 3 tesla MRI scanner using standard protocol which included T1-3D Turbo Field-Echo images with 1-mm slice thickness. The volumes of GM and white matter, total brain and the deep subcortical GM structures, including hippocampus, amygdala, caudate, putamen, globus pallidus and thalamus were extracted using a fully automated tool. Univariate analysis of covariance, adjusted for intracranial volume (ICV), sex and age, was used to explore group differences. Shape analysis was also performed using automated software with age, sex and total brain volume as covariates of no interest in the statistical design at P < 0.05 (FDR corrected). RESULTS: The patients with PSP had significantly lower volumes of bilateral thalami, hippocampus, pallidum and brainstem. Shape analysis of GM structures showed significant surface reduction in bilateral thalami and head of right caudate nucleus. CONCLUSIONS: MR volumetry showed abnormalities of various deep GM structures. Shape analysis also revealed focal surface contractions in multiple subcortical structures. Our study highlights the usefulness of this novel technique in detecting abnormalities of deep GM structures.


Subject(s)
Brain/pathology , Image Interpretation, Computer-Assisted/methods , Supranuclear Palsy, Progressive/pathology , Aged , Aged, 80 and over , Female , Humans , Magnetic Resonance Imaging , Male , Middle Aged
13.
Stem Cell Rev Rep ; 8(3): 696-705, 2012 Sep.
Article in English | MEDLINE | ID: mdl-21964568

ABSTRACT

Corneal transplantation with cultivated limbal or oral epithelium is a feasible treatment option for limbal stem cell deficiency (LSCD). Currently utilized co-culture of stem cells with murine 3T3 feeder layer renders the epithelial constructs as xenografts. To overcome the potential risks involved with xenotransplantation, we investigated the use of human-derived feeder layers for the ex vivo expansion of epithelial (stem) cells. Human limbal and oral epithelium was co-cultured with mouse 3T3 fibroblasts, human dermal fibroblasts (DF), human mesenchymal stem cells (MSC), and with no feeder cells (NF). Cell morphology was monitored with phase-contrast microscopy, and stem cell characteristics were assessed by immunohistochemistry, real-time PCR for p63 and ABCG2, (stem cell markers), and by colony-forming efficiency (CFE) assay. Immunohistochemical analysis detected positive staining for CK3 (cornea specific marker) and Iß1 and p63 (putative stem cell markers) in all culture conditions. The level of Iß1 and p63 was significantly higher in both limbal and oral cells cultured on the 3T3 feeder, as compared to the MSC or NF group (p<0.01). This level was comparable to the cells cultured on DF. Expression of p63 and ABCG2 in limbal and oral epithelial cells in the 3T3 and DF groups was significantly higher than that in the MSC or NF group (p<0.01). No statistical difference was detected between 3T3 and DF groups. The CFE of both limbal and oral cells co-cultured on 3T3 fibroblasts was comparable to cells grown on DF, and was significantly higher than that of cells co-cultured with MSC or NF (p<0.01). Epithelial cells grown on a DF feeder layer maintained a stem cell-like phenotype, comparable to cells grown on a 3T3 feeder layer. In conclusion, DF provides a promising substitute for 3T3 feeder cells during cultivation of xenobiotic-free corneal equivalents.


Subject(s)
Epithelium, Corneal/physiology , Feeder Cells/physiology , Fibroblasts/physiology , Limbus Corneae/cytology , Mouth Mucosa/cytology , 3T3 Cells , ATP Binding Cassette Transporter, Subfamily G, Member 2 , ATP-Binding Cassette Transporters/metabolism , Amnion/cytology , Animals , Cell Proliferation , Cell Shape , Coculture Techniques , Colony-Forming Units Assay , Dermis/cytology , Epithelium, Corneal/metabolism , Eye Diseases/therapy , Humans , Keratin-3/metabolism , Membrane Proteins/metabolism , Mesenchymal Stem Cells/metabolism , Mesenchymal Stem Cells/physiology , Mice , Neoplasm Proteins/metabolism , Tissue Culture Techniques
14.
Tetrahedron ; 67(39): 7461-7469, 2011 Sep 30.
Article in English | MEDLINE | ID: mdl-21918585

ABSTRACT

The iodination of chlorinated aromatic compounds using Ag(2)SO(4)/I(2), AgSbF(6)/I(2), AgBF(4)/I(2) and AgPF(6)/I(2) offers access to iodoarenes that are valuable intermediates in organic synthesis. Specifically, iodination of phenols, anisoles and anilines with a 3,5-dichloro substitution pattern preferentially yielded the ortho, para and para iodinated product, respectively. In the case of chlorobenzene and 3-chlorotoluene, AgSbF(6)/I(2), AgBF(4)/I(2) and AgPF(6)/I(2), but not Ag(2)SO(4)/I(2), selectively introduced the iodine in para position to the chlorine substituent.

15.
Colloids Surf B Biointerfaces ; 78(1): 75-84, 2010 Jun 15.
Article in English | MEDLINE | ID: mdl-20227859

ABSTRACT

The partitioning behavior of a series of perhydrocarbon nicotinic acid esters (nicotinates) between aqueous solution and dipalmitoylphosphatidylcholine (DPPC) membrane bilayers is investigated as a function of increasing alkyl chain length. The hydrocarbon nicotinates represent putative prodrugs, derivatives of the polar drug nicotinic acid, whose functionalization provides the hydrophobic character necessary for pulmonary delivery in a hydrophobic, fluorocarbon solvent, such as perfluorooctyl bromide. Independent techniques of differential scanning calorimetry and 1,6-diphenyl-1,3,5-hexatriene (DPH) fluorescence anisotropy measurements are used to analyze the thermotropic phase behavior and lipid bilayer fluidity as a function of nicotinate concentration. At increasing concentrations of nicotinates over the DPPC mole fraction range examined (X(DPPC)=0.6-1.0), all the nicotinates (ethyl (C2H5); butyl (C4H9); hexyl (C6H13); and octyl (C8H17)) partition into the lipid bilayer at sufficient levels to eliminate the pretransition, and decrease and broaden the gel to fluid phase transition temperature. The concentration at which these effects occur is chain length-dependent; the shortest chain nicotinate, C2H5, elicits the least dramatic response. Similarly, the DPH anisotropy results demonstrate an alteration of the bilayer organization in the liposomes as a consequence of the chain length-dependent partitioning of the nicotinates into DPPC bilayers. The membrane partition coefficients (logarithm values), determined from the depressed bilayer phase transition temperatures, increase from 2.18 for C2H5 to 5.25 for C8H17. The DPPC membrane/water partitioning of the perhydrocarbon nicotinate series correlates with trends in the octanol/water partitioning of these solutes, suggesting that their incorporation into the bilayer is driven by increasing hydrophobicity.


Subject(s)
1,2-Dipalmitoylphosphatidylcholine/chemistry , Esters/analysis , Lipid Bilayers/chemistry , Membranes, Artificial , Niacin/analysis , Prodrugs/analysis , Calorimetry, Differential Scanning , Diphenylhexatriene/chemistry , Fluorescence Polarization , Fluorescent Dyes/chemistry , Niacin/chemistry , Phase Transition , Transition Temperature
17.
J Chromatogr A ; 1207(1-2): 146-54, 2008 Oct 17.
Article in English | MEDLINE | ID: mdl-18760792

ABSTRACT

Several polychlorinated biphenyls (PCBs) and their hydroxylated metabolites display axial chirality. Here we describe an enantioselective, gas chromatographic separation of methylated derivatives of hydroxylated (OH-)PCB atropisomers (MeO-PCB) using a chemically bonded beta-cyclodextrin column (Chirasil-Dex). The atropisomers of several MeO-PCBs could be separated on this column with resolutions ranging from 0.42 to 0.87 under isothermal or temperature-programmed conditions. In addition, the enantiomeric fraction of OH-PCB 136 metabolites was determined in male and female rats treated with racemic PCB 136. The methylated derivatives of two OH-PCB 136 metabolites showed an enantiomeric enrichment in liver tissue, whereas PCB 136 itself was near racemic.


Subject(s)
Chromatography, Gas/methods , Liver/chemistry , Polychlorinated Biphenyls/analysis , Animals , Polychlorinated Biphenyls/chemistry , Polychlorinated Biphenyls/isolation & purification , Rats , Stereoisomerism
18.
Indian J Pediatr ; 75(11): 1171-4, 2008 Nov.
Article in English | MEDLINE | ID: mdl-18810351

ABSTRACT

A 5-year-old child admitted in the pediatric intensive care unit developed fever and crepitations in the chest on 6(th) day of admission. She succumbed to her illness depite administration of adequate supportive and ventilatory care and anti-microbial therapy. At autopsy, she was diagnosed to have chronic ligneous type of tuberculous meningitis and necrotizing adnoviral pneumonia. There are hardly any reports of nosocomial adenoviral pneumonia from Indian centers. The case serves to remind intensivists to consider this diagnosis so that appropriate therapeutic adjustments and measures to prevent the spread of infection to other critically ill subjects are initiated.


Subject(s)
Adenoviridae/isolation & purification , Adenovirus Infections, Human/virology , Cross Infection/diagnosis , Pneumonia, Viral/virology , Adenovirus Infections, Human/complications , Adenovirus Infections, Human/therapy , Child, Preschool , Cross Infection/prevention & control , Fatal Outcome , Female , Humans , India , Infection Control , Intensive Care Units, Pediatric , Pneumonia, Viral/complications , Pneumonia, Viral/pathology , Pneumonia, Viral/therapy , Tuberculosis, Meningeal/pathology
19.
Int J Pharm ; 353(1-2): 35-44, 2008 Apr 02.
Article in English | MEDLINE | ID: mdl-18164563

ABSTRACT

This study explores perfluorooctyl bromide (PFOB) as a potential vehicle for the pulmonary delivery of a series of prodrugs of nicotinic acid using cell culture studies. The prodrugs investigated have PFOB-water (logK(p)=0.78 to >2.2), perfluoromethylcyclohexane-toluene (logK(p)=-2.62 to 0.13) and octanol-water (logK(p)=0.90-10.2) partition coefficients spanning several orders of magnitude. In confluent NCI-H358 human lung cancer cells, the toxicity of prodrugs administered in culture medium or PFOB depends on the medium of administration, with EC20's above 8 mM and 2.5 mM for culture medium and PFOB, respectively. Short-chain nicotinates administered both in PFOB and medium increase cellular NAD/NADP levels at 1mM nicotinate concentrations. Long-chain nicotinates, which could not be administered in medium due to their poor aqueous solubility, increased NAD/NADP levels if administered in PFOB at concentrations > or =10 mM. These findings suggest that even highly lipophilic prodrugs can partition out of the PFOB phase into cells, where nicotinic acid is released and converted to NAD. Thus, PFOB may be a novel and biocompatible vehicle for the delivery of lipophilic prodrugs of nicotinic acid and other drugs directly to the lung of laboratory animals and humans.


Subject(s)
Fluorocarbons/administration & dosage , Lung/metabolism , Nicotinic Acids/administration & dosage , Prodrugs/administration & dosage , Cell Line, Tumor , Cell Survival/drug effects , Humans , Hydrocarbons, Brominated , NAD/analysis , NADP/analysis , Nicotinic Acids/chemical synthesis , Nicotinic Acids/chemistry , Nicotinic Acids/pharmacology , Pharmaceutical Vehicles , Prodrugs/chemical synthesis , Prodrugs/chemistry , Prodrugs/pharmacology , Solubility
20.
Article in English | MEDLINE | ID: mdl-17365291

ABSTRACT

Perfluorooctanesulfonyl (PFOS)-based materials and related compounds are an emerging group of environmental pollutants. Perfluorooctanesulfonyl fluoride, the key intermediate for the production of these materials, was manufactured by an electrochemical fluorination process that resulted in complex mixtures containing linear and branched PFOS derivatives and other perfluorinated compounds. This study uses 19F-NMR spectroscopy to investigate differences in the composition between commercial samples of PFOS and PFBS (perfluorobutanesulfonyl) derivatives. While PFBS derivatives, which are under evaluation as substitutes for PFOS-based materials, contained no detectable levels of branched impurities, all PFOS derivatives contained significant levels of branched and other impurities. Analysis of the NMR data reveals that PFOS fluorides typically have a higher content of internally branched and similar levels of isopropyl branched PFOS isomers compared to PFOS potassium salts. Furthermore, the isomer distribution of PFOS derivatives may vary depending on their source. These findings suggest that it is important to determine the isomer composition of PFOS samples used in both environmental and toxicological studies.


Subject(s)
Alkanesulfonic Acids/chemistry , Environmental Pollutants/chemistry , Fluorocarbons/chemistry , Isomerism , Magnetic Resonance Spectroscopy
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