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PubMed2000

Mechanisms for ion formation during the electron impact-mass spectrometry of picolinyl ester and 4,4-dimethyloxazoline derivatives of fatty acids.

Mass spectral studies have been conducted with isotopically stable labelled and fluorinated picolinyl esters and 4,4-dimethyloxazoline (DMOX) derivatives of fatty acids in order to establish mechanisms of ion formation. Reciprocal hydrogen transfer is shown to be involved in the formation of the ion at m/z 126 with dimethyloxazoline derivatives and for the ion at m/z 164 with picolinyl esters. Inclusion of a fluorine atom alpha to the carboxyl of a fatty acid has been demonstrated to enhance rearrangements for expulsion of internal chain fragments with both methyl ester and dimethyloxazoline derivatives. When two fluorine atoms are inserted into the alpha position a similar rearrangement has been shown to occur with picolinyl esters, although not nearly to the same extent as that observed with either of the other derivatives. Mechanisms for such rearrangements are proposed and discussed. With fatty acid dimethyloxazoline derivatives the M-15 ion arises solely from the loss of a methyl radical from the ring and the M-43 ion has at least three different mechanisms of formation. Such rearrangements make it difficult to establish the identity of the terminal moiety of the alkyl chain. In mass spectrometry terms the picolinyl ester would seem to be the superior derivative for structural characterisation of fatty acids.

Carbon Isotopes↗
PubMed2003

Derivatisation and gas chromatography-chemical ionisation mass spectrometry of selected synthetic and natural endocrine disruptive chemicals.

Methods for ultra trace detection of endocrine disruptive chemicals (EDCs) are needed because of their low levels of impact. Twenty-one EDCs were selected, including 17beta-estradiol, 17alpha-ethinylestradiol, 17beta-testosterone and bisphenol A. Derivatisation with eight different fluorine containing compounds was examined. All EDCs could be derivatised automatedly (autosampler) with heptafluorobutyric acid (HFB) anhydride and trifluoroacetic acid (TFA) anhydride, respectively. The detection of these HFB and TFA derivatives in different chemical ionisation modes was studied. Fourteen different reagent gases, including methane, ammonia, acetone and water, were tested with the HFB and TFA derivatives in the negative chemical ionisation mode. Furthermore both types of derivatives were measured in positive chemical ionisation mode. Methane or water provide a good detection of all 21 TFA derivatives and create mass spectra with few fragmentation and characteristic mass peaks. This could serve as a basis for tandem or multiple mass spectrometric measurements.

Acetic Anhydrides↗
PubMed1997

Preparation and use of ion-exchange chromatographic supports based on perfluoropolymers.

A poly(vinyl alcohol) (PVA) coated particulate perfluoropolymer (FEP) support has been functionalised with ion-exchange groups for use in ion-exchange chromatography of proteins. Anion-exchange (DEAE and Q) and cation-exchange (SP) groups were introduced to PVA-FEP which had previously been activated using cyanuric chloride. The equilibrium adsorption capacities of SP-PVA-FEP were 31.8 and 25.2 mg ml-1 for lysozyme and IgG respectively while for DEAE-PVA-FEP, the equilibrium adsorption capacities were 14.9 and 9.7 mg ml-1 for beta-lactoglobulin and HSA respectively. The equilibrium adsorption capacities for Q-PVA-FEP were determined to be 17.2 and 13.5 mg ml-1 for beta-lactoglobulin and HSA respectively. Experiments carried out to investigate the resolving power of materials showed that both SP and Q-PVA-FEP were able to resolve proteins with only small differences in their isoelectric points and that this resolution could be maintained at a flow-rate of 1500 cm h-1. SP-PVA-FEP was used to purify lysozyme from egg whites where a 50-fold purification, to homogeneity, was achieved in 98% yield. The anion exchanger, Q-PVA-FEP could be used to purify G6PDH from a clarified homogenate of bakers' yeast 14.3-fold in 81% yield.

Adsorption↗
PubMed2002

Solubilization of polycyclic aromatic hydrocarbons by perfluorinated surfactant micelles.

Due to their chemical and thermal stability, perfluorinated surfactants (PFSs) are promising materials for the development of novel environmental remediation applications. This stability also leads to the persistence of PFS in the environment; therefore, their properties and behavior should be well understood. This study focused on polycyclic aromatic hydrocarbon (PAH) and PFS interactions, particularly the solubilization of PAHs by PFS micelles. Naphthalene. phenanthrene, and pyrene were selected as representative PAHs and an anionic PFS, ammonium perfluorooctanoate (APFO) was used. Critical micelle concentration (CMC) values of APFO measured by surface tension, fluorescence probe, and solubility enhancement methods fell in the range of 20-30 mM at 22 +/- 1 degrees C. Apparent solubilities of molecular oxygen and PAHs in APFO micellar solutions depended linearly on the APFO concentration. Molar solubilization ratio (MSR) values were determined to be 9.50 x 10(-4), 4.17 x 10(-3), 2.31 x 10(-4), and 4.09 x 10(-5) and mole fraction micellar partition coefficient (Kmic) values were found to be 1.89 x 10(2), 9.50 x 10(2), 2.12 x 10(3), and 3.79 x 10(3) for oxygen, naphthalene, phenanthrene, and pyrene, respectively at 22 +/- 1 degrees C. log Kmic values for three PAHs were shown to be linearly correlated with the log values of octanol-water partition coefficients (log Kow).

Environmental Pollution↗
PubMed1996

Saturated and monofluoro analogs of the oriental fruit fly attractant methyl eugenol show reduced genotoxic activities in yeast.

Methyl eugenol, is a commercially used fruit fly attractant and a suspected carcinogen. Several phenylpropenes, including methyl eugenol and the known carcinogen safrole, score negative in the Salmonella assay but score positive in the yeast DEL assay that selects for intrachromosomal recombination events in the yeast Saccharomyces cerevisiae. In an attempt to dissociate the beneficial properties of methyl eugenol from its genotoxic properties, saturated or fluorinated analogs were evaluated for their ability to induce intrachromosomal (DEL) recombination in yeast. Field tests have previously shown that all of the analogs used have appreciable properties as fruit fly attractants. The analogs 1,2-dimethoxy-4-ethylbenzene, 1,2-dimethoxy-4-(2-fluoro-2-propenyl)benzene, 1,2-dimethoxy-4-(2-fluoroethyl)benzene and 1,2-dimethoxy-4-(3-fluoro-2-propenyl)benzene all showed reduced toxicity and reduced recombinagenicity in yeast compared to methyl eugenol. These results confirm the validity of fluorination and/or removal of the 2-propenyl moiety in reducing the toxicity and recombinagenicity of methyl eugenol derivatives.

Animals↗
PubMed1993

In vitro evaluation of inflammatory cell response after CF4 plasma surface modification of poly(methyl methacrylate) intraocular lenses.

The inflammatory cell response of tetrafluorocarbon (CF4) plasma surface modification of poly(methyl methacrylate) intraocular lenses (IOLs) was investigated in vitro. After two hours of lens contact with human granulocytes, scanning electron microscopy showed significantly less cell activation and granulocyte adhesion on the surface-modified IOL than on the untreated IOL (P < .01). The x-ray photo-electron spectroscopy analysis of the CF4 plasma surface modification demonstrated that new compounds containing fluorine were homogeneously grafted onto the PMMA lens surface, resulting in a marked increase of contact angle. These in vitro results must be confirmed by in vivo studies of CF4 plasma surface modification of IOLs.

Biocompatible Materials↗
PubMed2003

Design and synthesis of fluorinated RXR modulators.

Fluorinated trienoic acid analogues of the RXR selective modulator 1 (LG101506) were synthesized, and tested for their ability to bind RXRalpha and activate RXR homo and heterodimers. Potency and efficacy were observed to be dependent upon the position of fluorination, and improvement in pharmacological profile was demonstrated in some cases.

Animals↗
PubMed1999

Synthesis and biological evaluation of 1,1-difluoro-2-(tetrahydro-3-furanyl)ethylphosphonic acids possessing a N9-purinylmethyl functional group at the ring. a new class of inhibitors for purine nucleoside phosphorylases.

1,1-Difluoro-2-(tetrahydro-3-furanyl)ethylphosphonic acids cis-3 and trans-3 possessing a N9-purinylmethyl functionality at the ring were synthesized and tested as "multi-substrate analogue" inhibitors for purine nucleoside phosphorylases. Radical cyclization of allyic alpha,alpha-difluorophosphonate (E)-7 was applied to construct the alpha,alpha-difluorophosphonate-functionalized tetrahydrofuranyl moiety. The IC50 values of cis-3 and trans-3 for human erythrocyte PNP-catalyzed phosphorylation of inosine were determined to be 88 and 320 nM, respectively. The stereochemistry of the inhibitors was found to affect significantly the inhibitory potency.

Antineoplastic Agents↗
PubMed1994

Silyl protection in the solid-phase synthesis of N-linked glycopeptides. Preparation of glycosylated fluorogenic substrates for subtilisins.

The trimethylsilyl (TMS) group was used for protection of the hydroxy groups of three disaccharide 1-amino-alditols and of the glycosylamines of glucose, maltotriose and maltoheptose. The per-O-trimethylsilylated derivatives were coupled with N alpha-Fmoc-Asp(Cl)-OPfp 7 to give six glycosylated building blocks for the solid-phase synthesis of N-linked glycopeptides. Building block 8 was used in the synthesis of five internally quenched fluorescent substrates which were studied by enzymatic hydrolysis with savinase, a subtilisin-type enzyme.

Amino Acid Sequence↗
PubMed1992

Inhibition of aromatic amino acid decarboxylase by a group of non-steroidal anti-inflammatory drugs.

In vitro inhibition of aromatic amino acid decarboxylase (AAD) by eight nonsteroidal anti-inflammatory drugs (NSAIDs) was studied. The most potent inhibitors were fenamates (IC50 for tolfenamate was 4.4 x 10(-5) M), while fluorinated biphenylic compounds (flobufen and 2',4'-difluorobiphenyl-4-yl acetate) and propionic acid derivatives (ibuprofen, ketoprofen, fenoprofen) were one order weaker. The in vitro inhibition of AAD by the compounds studied is probably not strong enough to contribute to their in vivo anti-inflammatory effects.

Animals↗
PubMed2000

Towards the nonstick egg: designing fluorous proteins.

Anyone who has made scrambled eggs will have had cause to praise the properties of Teflon. Teflon's highly chemically inert and nonstick nature derives from the perfluorinated polymer polytetrafluoroethylene. Perfluorocarbons have unique and valuable physical properties not found in nature. By incorporating fluorine into proteins, it might be possible to produce biological molecules with novel and useful properties.

Fluorine Compounds↗
PubMed2003

Two-dimensional Hadamard spectroscopy.

Direct frequency-domain excitation of NMR with an array of different radiofrequencies has been used to speed up two-dimensional NMR experiments by a large factor. Multiplex excitation in the F(1) frequency dimension is restricted to the signal-bearing regions and is encoded according to a Hadamard matrix of dimension N by N, where N is a relatively small number. The detected signals are decoded by reference to the same Hadamard matrix. Alternatively a phase-encoding scheme can be employed. Two-dimensional correlation experiments (COSY and TOCSY) and cross-relaxation measurements (NOESY) implemented on proton systems can be completed in less than a minute in cases where the intrinsic sensitivity is sufficiently high that prolonged multiscan averaging is not required. The results are presented in the form of a high-resolution contour diagram similar to the familiar two-dimensional spectra obtained by Fourier transform methods. Experiments on strychnine demonstrate more than two orders of magnitude improvement in speed compared with the traditional methods.

Algorithms↗
PubMed2026

Long-term safety of oral orforglipron in Japanese participants with type 2 diabetes (ACHIEVE-J): a multicentre, randomised, open-label, parallel-group phase 3 trial.

BACKGROUND: Orforglipron, an oral GLP-1 receptor agonist, requires further evaluation in east Asian populations with type 2 diabetes, given this group's distinct pathophysiological characteristics. This study aimed to assess orforglipron as add-on treatment to diet and exercise alone or to oral antihyperglycaemic medications in Japanese participants with type 2 diabetes. METHODS: This multicentre, randomised, open-label phase 3 study was conducted in 40 medical research centres and hospitals in Japan. Adults with type 2 diabetes and elevated glucose levels managing their condition with diet and exercise alone or with one or two oral antihyperglycaemic medications were assigned (1:1:1) via computer-generated random sequence to receive once-daily oral orforglipron (3 mg, 12 mg, or 36 mg). Randomisation was stratified by background therapy, baseline HbA1c (&#x2264;8&#xb7;5% or >8&#xb7;5%), and metformin use (yes vs no; applied only to &#x3b1;-glucosidase inhibitors, thiazolidinedione, and glinides). Investigators, participants, and site staff were not masked to treatment. The primary endpoint was safety for 52 weeks, assessed in all randomly assigned participants who received at least one dose of orforglipron. This study is registered with ClinicalTrials.gov, NCT06010004 (ACHIEVE-J). FINDINGS: Between Sept 28, 2023, and June 5, 2025, 450 participants were screened and 401 were randomly assigned to three groups (3 mg, n=132; 12 mg, n=135; and 36 mg, n=134). 352 (88%) completed study treatment. 339 participants (85%, 95% CI 80&#xb7;7-87&#xb7;8) had at least one treatment-emergent adverse event (TEAE), more frequently in the 36-mg group (118 [88%, 95% CI 81&#xb7;5-92&#xb7;5]) than in the 3-mg (107 [81%, 73&#xb7;5-86&#xb7;8]) and 12-mg (114 [84%, 77&#xb7;4-89&#xb7;6]) groups. Most TEAEs were of mild (267 [67%, 61&#xb7;8-71&#xb7;0]) or moderate (63 [16%, 12&#xb7;5-19&#xb7;6]) severity. Discontinuations due to an adverse event occurred in 19 of 134 participants (14%, 95% CI 9&#xb7;3-21&#xb7;1) in the 36-mg group compared with seven of 132 (5%, 2&#xb7;6-10&#xb7;5) in the 3-mg group and 11 of 135 (8%, 4&#xb7;6-14&#xb7;0) in the 12-mg group. Across treatment groups, gastrointestinal symptoms were the most common TEAEs leading to study treatment discontinuation (3 mg: 5 [3&#xb7;8%, 1&#xb7;6-8&#xb7;6]; 12 mg: 8 [5&#xb7;9%, 3&#xb7;0-11&#xb7;3]; and 36 mg: 11 [8&#xb7;2%, 4&#xb7;7-14&#xb7;1]). Level 2 (blood glucose <54 mg/dL) hypoglycaemia events occurred in three of 135 participants in the 12-mg group (2%, 0&#xb7;8-6&#xb7;3) and in three of 134 in the 36-mg group (2%, 0&#xb7;8-6&#xb7;4) groups. No level 3 (severe) hypoglycaemia events occurred. Outcomes were generally similar across background therapies. INTERPRETATION: Treatment with orforglipron in combination with diet and exercise alone or one or two oral antihyperglycaemic medications for 52 weeks demonstrated an acceptable safety profile in Japanese adults with type 2 diabetes. FUNDING: Eli Lilly. TRANSLATION: For the Japanese translation of the abstract see Supplementary Materials section.

Aged↗
PubMed2005

Measurement of 18 perfluorinated organic acids and amides in human serum using on-line solid-phase extraction.

We have developed an on-line solid-phase extraction (SPE) method coupled to high-performance liquid chromatography (HPLC)-tandem mass spectrometry (MS/MS) for measuring trace levels of 18 perfluorinated chemicals (3 perfluorosulfonates, 8 perfluorocarboxylates, 7 perfluorosulfonamides) in serum. Without protein precipitation, only dilution with 0.1 M formic acid, one aliquot of 100 microL of serum was injected into a commercial column switching system that allowed for concurrent SPE and HPLC-MS/MS acquisition. First, the analytes were concentrated on a C18 SPE column. Then, this column was placed automatically in front of a C8 analytic HPLC column for chromatographic separation of the analytes. Detection and quantification were done using negative-ion TurboIonSpray ionization, a variant of electrospray ionization, MS/MS. Excellent recovery was achieved for all analytes including the volatile sulfonamide derivatives that could not be determined before using traditional off-line SPE methods. The high throughput and low limits of detection (0.05-0.8 ng/mL) using a small sample volume (100 microL of serum) and isotope dilution quantification make this method suitable for large-scale epidemiologic studies.

Acids↗
PubMed2005

Modification of micronozzle surfaces using fluorinated polymeric nanofilms for enhanced dispensing of polar and nonpolar fluids.

In this work, we report on the surface modification of a micronozzle surface to enhance fluid dispensing in the nanoliter range. Unmodified dispensing chips usually suffer from lateral wetting of the nozzle surfaces by low surface tension liquids resulting in poor control of the volume of the dispensed fluid. Covalent attachment of a fluorinated acrylate polymer to the outer surface of the micronozzle using a novel UV irradiation process helps to overcome capillary and adhesive forces and results in an enhancement of the control on fluid dispensing in the nanoliter range. The modified nozzles have been tested with a variety of fluids having a wide range of surface tensions. The surface modification allows precise control of the dispensing of nanoliter droplets with a high degree of reproducibility.

Fluorine Compounds↗