bluuebunny/crossref_metadata_2025_split huggingface dataset:
Determination of stavudine in human serum by on‐line solid‐phase extraction coupled to high‐performance liquid chromatography with electrospray ionization tandem mass spectrometry: application to a bioequivalence study
Authors: Raices Renata S. L. , Salvadori Myriam C. , Estrela Rita de Cassia E. , Neto Francisco R. de Aquino , Suarez‐Kurtz Guilherme 
Published: July 2003

AbstractA method based on solid‐phase extraction (SPE) coupled to high‐performance liquid chromatography (HPLC) with positive ion electrospray ionization tandem mass spectrometry (ESI‐MS/MS) detection was developed for the determination of stavudine in human serum, using didanosine as internal standard. The acquisition was performed in multiple reaction monitoring (MRM) mode. The method was linear over the studied range (10–2000 ng/mL), with r2 > 0.99, and the run time was 4 min. The intra‐ and inter‐assay precisions (%) were in the ranges 0.1–13.6 and 2.6–9.9, respectively, and the intra‐ and inter‐assay accuracies were >92%. The absolute recoveries were approximately 100% (10 ng/mL), 98% (30 ng/mL), 105% (750 ng/mL) and 105% (1500 ng/mL). The limits of detection and quantitation were 4 and 10 ng/mL, respectively. The analytical method was applied to a bioequivalence study, in which 24 healthy adult volunteers (12 men) received single oral doses (40 mg) of reference and two test stavudine formulations, in an open, three‐period, randomized, crossover protocol. The 90% confidence interval of the individual ratios (test formulation/reference formulation) for Cmax (peak serum concentration), AUC0–10 and AUC0–inf (areas under the serum concentration vs. time curve from time zero to 10 h and to infinity, respectively), were in the range 80–125%, which supports the conclusion that the two test formulations are bioequivalent to the reference formulation with respect to the rate and extent of stavudine absorption. Copyright © 2003 John Wiley & Sons, Ltd.
Investigations into the use of a reverse scan in a quadrupole ion trap mass spectrometer
Authors: Dobson G. , Murrell J. , Despeyroux D. , Wind F. , Tabet J.‐C. 
Published: July 2003

AbstractThe forward scan (i.e. an increasing RF voltage ramp for the mass‐selective instability scan) is commonly used as an analytical scan for ion detection with quadrupole ion trap instruments. A number of phenomena have been observed while using this scan technique. These include space charge effects resulting in the delayed ejection of ions from the ion trap, and the fragmentation of fragile ions producing very broad peaks. Here the use of a reverse scan (i.e. a decreasing RF voltage ramp) is examined to determine the effect of the above phenomena in this acquisition method. With regard to space charge effects, the apparent reduction of the carbon isotope spacing below one Thomson (for singly charged ions) that is observed with the forward scan is now replaced by an apparent increase in this spacing. The reverse scan, which optimizes at lower axial modulation ejection voltages than the forward scan, allows for the intact ejection of fragile ions under its typical operating conditions whereas the forward scan results in fragmentation. Reducing the axial modulation voltage for the ejection of ions in the forward scan results in less dissociation of the fragile ions during ion ejection, but with the observation of ghost peaks due to incomplete ejection of all of the ions at the resonance ejection condition. While performing the reverse scan experiment, the formation of product ions from dissociation of the MH+ ion has also been observed. Copyright © 2003 John Wiley & Sons, Ltd.
The Making of a Martyr: The Legend of Meyerhold's Last Public Appearance
Authors: SENELICK LAURENCE 
Published: July 2003

The disappearance of Meyerhold into the Soviet prison system in 1939 fostered
legends, which contributed to his rehabilitation as a martyr. A primary contribution to this
process was a fictional account of his defiant speech at the All-Soviet Directors'
Conference a few days before his arrest. The speech, made up out of whole cloth by
the émigré musician Yury Elagin in 1951, gained considerable currency
and was circulated as Cold War propaganda. It was not wholly discredited until the 1990s, when
the publication of the stenographic transcript of the Conference proceedings
revealed Meyerhold's actual capitulation to Stalinist artistic policy and his poor
showing on the podium.As I was going up the stairI met a man who wasn't there.He wasn't there again today.I wish, I wish he'd stay away.Hughes Mearns
Properties of NO‐activated guanylyl cyclases expressed in cells
Authors: Gibb Barry J , Wykes Victoria , Garthwaite John 
Published: July 2003

Physiological nitric oxide (NO) signal transduction occurs through activation of guanylyl cyclase (GC)‐coupled receptors, resulting in cGMP accumulation. There are five possible receptors: four heterodimers (α1β1, α2β1, α1β2, α2β2) and a presumed homodimer (νβ2). The present study investigated the kinetic and pharmacological properties of all these putative receptors expressed in COS‐7 (or HeLa) cells.
All exhibited NO‐activated GC activity, that of α1β1 and α2β1 being much higher than that of the β2‐containing heterodimers or νβ2. All were highly sensitive NO detectors. Using clamped NO concentrations, EC50 values were 1 nM for α1β1 and 2 nM for α2β1. With α1β2, α2β2 and νβ2, the EC50 was estimated to be lower, about 8 nM.
All the GCs displayed a marked desensitising profile of activity. Consistent with this property, the concentration–response curves were bell‐shaped, particularly those of the β2 heterodimers and νβ2.
Confocal microscopy of cells transfected with the fluorescently tagged β2 subunit suggested targeting to the endoplasmic reticulum through its isoprenylation sequence, but no associated particulate GC activity was detected.
The NO‐stimulated GC activity of all heterodimers and νβ2 was inhibited by 1H‐[1,2,4]oxadiazolo[4,3‐a]quinoxalin‐1‐one and, except for νβ2, was enhanced by the allosteric activator YC‐1.
It is concluded that all the four possible heterodimers, as well as the putative νβ2 homodimer, can function as high‐affinity GC‐coupled NO receptors when expressed in cells. They exhibit differences in NO potency, maximal GC activity, desensitisation kinetics and possibly subcellular location but, except for νβ2, cannot be differentiated using existing pharmacological agents.

British Journal of Pharmacology (2003) 139, 1032–1040. doi:10.1038/sj.bjp.0705318
Modulation of ATP‐induced currents by zinc in acutely isolated hypothalamic neurons of the rat
Authors: Vorobjev Vladimir S , Sharonova Irina N , Sergeeva Olga A , Haas Helmut L 
Published: July 2003

Whole‐cell patch‐clamp and fast perfusion were used to study the effects of zinc on adenosine 5′‐triphosphate (ATP)‐induced responses of histaminergic neurons.
At 10–30 μM ATP, Zn2+ had biphasic effects on ATP responses. Zn2+ at 3–100 μM increased the ATP‐induced currents, but inhibited them at higher concentrations.
At 300 μM ATP, Zn2+ predominantly but incompletely inhibited the currents.
At 5 and 50 μM, Zn2+ shifted to the left the concentration–response curve for ATP‐induced currents, without changing the maximal response. At 1 mM, Zn2+ inhibited ATP‐induced currents in a noncompetitive way, reducing the maximal response by 58%.
Zn2+ increased the decay time of ATP‐evoked currents nine fold with an EC50 of 63 μM. Upon removal of high concentrations of Zn2+, there was a rapid increase of the current followed by a slow decline towards the response amplitude seen with ATP alone. The appearance of a tail current is consistent with a Zn2+‐induced increase of ATP affinity and an inhibition of its efficacy.
Thus, Zn2+ acts as a bidirectional modulator of ATP receptor channels in tuberomamillary neurons, which possess functional P2X2 receptors. The data are consistent with the existence of two distinct modulatory sites on the P2X receptor, which can be occupied by Zn2+.
Our data suggest that zinc‐induced potentiation of ATP‐mediated currents is caused by the slowing of ATP dissociation from the receptor, while inhibition of ATP‐induced currents is related to the suppression of ATP receptor gating.

British Journal of Pharmacology (2003) 139, 919–926. doi:10.1038/sj.bjp.0705321
Endothelin‐1 inhibits TNFα‐induced iNOS expression in 3T3‐F442A adipocytes
Authors: Mérial‐Kieny Christelle , Lonchampt Michel , Cogé Francis , Verwaerde Patrick , Galizzi Jean‐Pierre , Boutin Jean A , Lafontan Max , Levens Nigel , Galitzky Jean , Félétou Michel 
Published: July 2003

Endothelin‐1 (ET‐1) and tumor necrosis factor α (TNFα) by their action on adipocytes have been independently linked to the pathogenesis of insulino‐resistance. In isolated adipocytes, TNFα induces the expression of the inducible nitric oxide synthase (iNOS). The purpose of the present work was, in the 3T3‐F442A adipocyte cell line, to characterise TNFα‐induced iNOS expression and to determine whether or not ET‐1 could influence TNFα‐induced iNOS expression and NO production.
In differentiated 3T3‐F442A, treatment with TNFα (20 ng ml−1) induced the expression of a functional iNOS as demonstrated by nitrite assay, Western blot, reverse transcription–polymerase chain reaction and Northern blot analysis. TNFα‐induced iNOS expression requires nuclear factor κB activation, but does not necessitate the activation of the PI‐3 kinase/Akt and P38–MAP kinase pathways.
ET‐1, but not ET‐3, inhibited the TNFα‐induced expression of iNOS protein and mRNA as well as nitrite production. The effects of ET‐1 were blocked by a specific ETA (BQ123, pA2 7.4) but not by a specific ETB receptor antagonist (BQ788). 3T3‐F442A adipocytes express the mRNAs for prepro‐ET‐1 and the ET‐A receptor subtype, but not for the ET‐B subtype.
The inhibitory effect of ET‐1 was not affected by bisindolylmaleimide, SB 203580 or indomethacin, inhibitors of protein kinase C, p38‐MAP kinase and cyclooxygenase, respectively, and was not associated with cAMP production. However, the effect of ET‐1 was partially reversed by wortmannin, suggesting the involvement of PI3 kinase in the transduction signal of ET‐1.
Differentiated 3T3‐F442A adipocytes did not release ET‐1 with or without exposure to TNFα, although the mRNA for preproET‐1 was detected in both pre‐ and differentiated adipocytes.
Thus, these results confirm that adipocytes are a target for circulating ET‐1 and demonstrate that the activation of the ETA receptor subtype can prevent TNFα‐induced iNOS expression.

British Journal of Pharmacology (2003) 139, 935–944. doi:10.1038/sj.bjp.0705325
Docosahexaenoic acid and arachidonic acid release in rat brain astrocytes is mediated by two separate isoforms of phospholipase A2 and is differently regulated by cyclic AMP and Ca2+
Authors: Strokin Mikhail , Sergeeva Marina , Reiser Georg 
Published: July 2003

Docosahexaenoic acid (DHA) and arachidonic acid (AA), polyunsaturated fatty acids (PUFAs), are important for central nervous system function during development and in various pathological states. Astrocytes are involved in the biosynthesis of PUFAs in neuronal tissue. Here, we investigated the mechanism of DHA and AA release in cultured rat brain astrocytes.
Primary astrocytes were cultured under standard conditions and prelabeled with [14C]DHA or with [3H]AA. Adenosine 5′‐triphosphate (ATP) (20 μM applied for 15 min), the P2Y receptor agonist, stimulates release of both DHA (289% of control) and AA (266% of control) from astrocytes. DHA release stimulated by ATP is mediated by Ca2+‐independent phospholipase A2 (iPLA2), since it is blocked by the selective iPLA2 inhibitor 4‐bromoenol lactone (BEL, 5 μM) and is not affected either by removal of Ca2+ from extracellular medium or by suppression of intracellular Ca2+ release through PLC inhibitor (U73122, 5 μM).
AA release, on the other hand, which is stimulated by ATP, is attributed to Ca2+‐dependent cytosolic PLA2 (cPLA2). AA release is abolished by U73122 and, by removal of extracellular Ca2+, is insensitive to BEL and can be selectively suppressed by methyl arachidonyl fluorophosphonate (3 μM), a general inhibitor of intracellular PLA2 s.
Western blot analysis confirms the presence in rat brain astrocytes of 85 kDa cPLA2 and 40 kDa protein reactive to iPLA2 antibodies.
The influence of cAMP on regulation of PUFA release was investigated. Release of DHA is strongly amplified by the adenylyl cyclase activator forskolin (10 μM), and by the protein kinase A (PKA) activator dibutyryl‐cAMP (1 mM). In contrast, release of AA is not affected by forskolin or dibutyryl‐cAMP, but is almost completely blocked by 2,3‐dideoxyadenosine (20 μM) and inhibited by 34% by H89 (10 μM), inhibitors of adenylyl cyclase and PKA, respectively.
Other neuromediators, such as bradykinin, glutamate and thrombin, stimulate release of DHA and AA, which is comparable to the release stimulated by ATP.
Different sensitivities of iPLA2 and cPLA2 to Ca2+ and cAMP reveal new pathways for the regulation of fatty acid release and reflect the significance of astrocytes in control of DHA and AA metabolism under normal and pathological conditions in brain.

British Journal of Pharmacology (2003) 139, 1014–1022. doi:10.1038/sj.bjp.0705326
Pharmacological profile of store‐operated channels in cerebral arteriolar smooth muscle cells
Authors: Flemming R , Xu S Z , Beech D J 
Published: July 2003

In this study, we determined a pharmacological profile of store‐operated channels (SOCs) in smooth muscle cells of rabbit pial arterioles. Ca2+‐indicator dyes, fura‐PE3 or fluo‐4, were used to track [Ca2+]i and 10 μM methoxyverapamil (D600) was present in all experiments on SOCs to prevent voltage‐dependent Ca2+ entry. Store depletion was induced using thapsigargin or cyclopiazonic acid.
SOC‐mediated Ca2+ entry was inhibited concentration dependently by Gd3+ (IC50 101 nM). It was also inhibited by 10 μM La3+ (70% inhibition, N=5), 100 μM Ni2+ (57% inhibition, N=5), 75 μM 2‐aminoethoxydiphenylborate (66% inhibition, N=4), 100 μM capsaicin (12% inhibition, N=3) or preincubation with 10 μM wortmannin (76% inhibition, N=4). It was completely resistant to 1 μM nifedipine (N=5), 10 μM SKF96365 (N=6), 10 μM LOE908 (N=14), 10–100 μM ruthenium red (N=1+2), 100 μM sulindac (N=4), 0.5 mM streptomycin (N=3) or 1 : 10,000 dilution Grammostolla spatulata venom (N=4).
RT–PCR experiments on isolated arteriolar fragments showed expression of mRNA species for TRPC1, 3, 4, 5 and 6.
The pharmacological profile of SOC‐mediated Ca2+ entry in arterioles supports the hypothesis that these SOCs are distinct from tonically active background channels and several store‐operated and other nonselective cation channels described in other cells. Similarities with the pharmacology of TRPC1 support the hypothesis that TRPC1 is a subunit of the arteriolar smooth muscle SOC.>

British Journal of Pharmacology (2003) 139, 955–965. doi:10.1038/sj.bjp.0705327
Lipid‐lowering properties of TAK‐475, a squalene synthase inhibitor, in vivo and in vitro
Authors: Nishimoto Tomoyuki , Amano Yuichiro , Tozawa Ryuichi , Ishikawa Eiichiro , Imura Yoshimi , Yukimasa Hidefumi , Sugiyama Yasuo 
Published: July 2003

Squalene synthase is the enzyme that converts farnesyl pyrophosphate to squalene in the cholesterol biosynthesis pathway. We examined the lipid‐lowering properties of 1‐[[(3R,5S)‐1‐(3‐acetoxy‐2,2‐dimethylpropyl)‐7‐chloro‐5‐(2,3‐dimethoxyphenyl)‐2‐oxo‐1,2,3,5‐tetrahydro‐4,1‐benzoxazepin‐3‐yl]acetyl]piperidine‐4‐acetic acid (TAK‐475), a novel squalene synthase inhibitor.
TAK‐475 inhibited hepatic cholesterol biosynthesis in rats (ED50, 2.9 mg kg−1) and showed lipid‐lowering effects in beagle dogs, marmosets, cynomolgus monkeys and Wistar fatty rats.
In marmosets, TAK‐475 (30, 100 mg kg−1, p.o., for 4 days) lowered both plasma non‐high‐density lipoprotein (HDL) cholesterol and triglyceride, but did not affect plasma HDL cholesterol. On the other hand, atorvastatin (10, 30 mg kg−1, p.o., for 4 days) lowered the levels of all these lipids. A correlation between decrease in triglyceride and increase in HDL cholesterol was observed, and TAK‐475 increased HDL cholesterol with a smaller decrease in triglyceride than did atorvastatin.
TAK‐475 (60 mg kg−1, p.o., for 15 days) suppressed the rate of triglyceride secretion from the liver in hypertriglyceridemic Wistar fatty rats, which show an enhanced triglyceride secretion rate from the liver compared with their lean littermates.
In HepG2 cells, TAK‐475 and its pharmacologically active metabolite, T‐91485, increased the binding of 125I‐low‐density lipoprotein (LDL) to LDL receptors.
6 These results suggest that TAK‐475 has clear hypolipidemic effects in animals via inhibition of hepatic triglyceride secretion and upregulation of LDL receptors, and that TAK‐475 might increase HDL cholesterol by decreasing triglyceride. Thus, TAK‐475 is expected to be useful for the treatment of dyslipidemia.

British Journal of Pharmacology (2003) 139, 911–918. doi:10.1038/sj.bjp.0705332
On the estimation variance for the specific Euler–Poincaré characteristic of random networks
Authors: Tscheschel A. , Stoyan D. 
Published: July 2003

SummaryThe specific Euler number is an important topological characteristic in many applications. It is considered here for the case of random networks, which may appear in microscopy either as primary objects of investigation or as secondary objects describing in an approximate way other structures such as, for example, porous media. For random networks there is a simple and natural estimator of the specific Euler number. For its estimation variance, a simple Poisson approximation is given. It is based on the general exact formula for the estimation variance. In two examples of quite different nature and topology application of the formulas is demonstrated.
Measurement of the electric field distribution and potentials on the object surface in an emission electron microscope without restriction of the electron beams
Authors: Nepijko S. A. , Gloskovskii A. , Sedov N. N. , Schönhense G. 
Published: July 2003

SummaryAn emission electron microscope without restriction of the electron beams was used to visualize and measure the distribution of electric fields and potentials on the surface under study. Investigations of this kind can be performed in an emission electron microscope without any aperture diaphragm. The potentialities of this method have been demonstrated using measurements with a silicon p–n junction to which a voltage has been applied in the reverse direction. The quantitative analysis becomes more complicated if the specimen is characterized by a heterogeneous intensity distribution of the electron emission from different areas of its surface. In the latter case two images obtained at different accelerating voltages (i.e. different voltages of the microscope extractor) provide the information necessary for an analysis of electric field and potential distributions.
The maintenance and preservation of keratinophilic fungi and related dermatophytes
Authors: Deshmukh S. K. 
Published: July 2003

SummaryA total of 239 fungi belonging to nine genera and 23 species were maintained on agar slopes in a refrigerator at +8 ± 1 °C and in sterile distilled water, under liquid paraffin, dried on silica gel, in sterile soil at room temperature. A limited number has been stored by freeze‐drying between 1985 and 1998. It is recommended that each isolate should be maintained by at least two of these methods. The choice of the method will depend to a large extent on the equipment and facilities available in the laboratory. It is reported that simple methods can be used for preservation of keratinophilic fungi and related dermatophytes.
An epidemiological and clinical study of untreated patients with tinea pedis within a company in Japan
Authors: Maruyama R , Hiruma M , Yamauchi K , Teraguchi S , Yamaguchi H 
Published: July 2003

SummaryIn this study, we investigated epidemiological and clinical aspects of dermatophyte foot infections among employees of one dairy product company located in Kanagawa prefecture in central Japan. Sixty‐nine of 377 subjects were reported having “athlete's foot” in response to a simple questionnaire. A subsequent mycological examination revealed 41 untreated patients with tinea pedis and/or tinea unguium (89% of subjects examined) and the overall prevalence was estimated at 18%. Comparing severity scores of five clinical symptoms (itching, erythema, vesicles/pustules, erosion/maceration, and scales) between those untreated patients within the subjects and another group of patients who spontaneously attended dermatological clinics to treat tinea pedis, itching, erythema, and total score were significantly higher in the latter group.
Subcutaneous phaeohyphomycosis on face caused by Cladophialophora bantiana
Authors: Jain S. K. , Agrawal S. C. , Jain P. C. 
Published: July 2003

SummaryWe report the case of a patient suffering from subcutaneous phaeohyphomycosis caused by Cladophialophora bantiana. The face of the upper site was involved with small, stellate, pyogranulomatous foci and low inflammation. The patient was treated by topical and systemic corticosteriod and amphotericin B. After 3 months of treatment, the patient showed good response.
What is the significance of an isolated positive cryptococcal antigen in the cerebrospinal fluid of cancer patients?
Authors: Kontoyiannis Dimitrios P. 
Published: July 2003

SummaryWe evaluated the significance of an isolated positive cryptococcal antigen titer in the cerebrospinal fluid (CSF) of 12 cancer patients. In most of the cases, the test had a low titer, was frequently associated with an intracranial malignancy and was considered to represent a false‐positive result. Hence, an isolated cryptococcal antigen in the CSF has an unclear clinical value and must be interpreted with caution.
Pilin-Like Proteins in the Extremely Thermophilic Bacterium
Thermus thermophilus
HB27: Implication in Competence for Natural Transformation and Links to Type IV Pilus Biogenesis
Authors: Friedrich Alexandra , Rumszauer Judit , Henne Anke , Averhoff Beate 
Published: July 2003

ABSTRACT

The extreme thermophile
Thermus thermophilus
HB27 exhibits high frequencies of natural transformation. Although we recently reported identification of the first competence genes in
Thermus
, the molecular basis of DNA uptake is unknown. A pilus-like structure is assumed to be involved. Twelve genes encoding prepilin-like proteins were identified in three loci in the genome of
T. thermophilus
. Mutational analyses, described in this paper, revealed that one locus, which contains four genes that encode prepilin-like proteins (
pilA1
to
pilA4
), is essential for natural transformation. Additionally,
comZ
, a new competence gene with no similarity to known genes, was identified. Analysis of the piliation phenotype revealed wild-type piliation of a
pilA1-pilA3
Δ
kat
mutant and a
comZ
mutant, whereas a
pilA4
mutant was found to be completely devoid of pilus structures. These findings, together with the significant similarity of PilA4 to prepilins, led to the conclusion that the
T. thermophilus
pilus structures are type IV pili. Furthermore, the loss of the transformation and piliation phenotype in the
pilA4
mutant suggests that type IV pili are implicated in natural transformation of
T. thermophilus
HB27.