bluuebunny/crossref_metadata_2025_split huggingface dataset:
T‐1032, a cyclic GMP phosphodiesterase‐5 inhibitor, acutely blocks physiologic insulin‐mediated muscle haemodynamic effects and glucose uptake in vivo
Authors: Mahajan Hema , Richards Stephen M , Rattigan Stephen , Clark Michael G 
Published: November 2003

Cyclic GMP phosphodiesterase‐5 inhibitors have been shown to alter blood flow in specific tissues by potentiating local NO‐dependent vasodilatory mechanisms. Since the haemodynamic effects of physiologic insulin, particularly capillary recruitment, may be critical for muscle glucose uptake in vivo and are blocked by inhibitors of nitric oxide synthase, we have explored the acute effects of the specific cGMP phosphodiesterase‐5 inhibitor T‐1032 on physiologic insulin action in anaesthetized healthy rats in vivo.
Whole‐body glucose infusion (GIR), femoral blood flow (FBF), hind leg vascular resistance (VR), hind leg glucose uptake (HGU), 2‐deoxyglucose uptake into muscles of the lower leg (R′g), hind leg metabolism of infused 1‐methylxanthine (1‐MX), a measure of capillary recruitment, and muscle cGMP were determined. The experimental groups were T‐1032 (10 μg min−1 kg−1) infused for 1 h before and during a euglycaemic insulin clamp (3 mU min−1 kg−1 × 2 h), T‐1032 infused for 3 h with saline, T‐1032 during a 2 h clamp, T‐1032 with saline for 2 h, and a 2 h saline control.
Insulin increased GIR from zero to 13 mg min−1 kg−1, HGU from 0.1±0.01 to 0.43±0.05 μmol min−1, R′g and 1‐MX, marginally increased FBF, and had no effect on blood pressure or heart rate. T‐1032 alone had no effect on blood pressure, heart rate, FBF, VR, HGU, R′g or 1‐MX, but increased muscle cGMP. T‐1032 1 h before and during insulin completely blocked GIR (1 h), HGU (2 h), R′g (2 h), and 1‐MX (2 h). T‐1032 commenced with insulin had only partial blocking activity against insulin.
We conclude that T‐1032 is a potent acutely acting inhibitor of the muscle effects of physiologic insulin on capillary recruitment and glucose uptake in vivo. These, together with inhibition of whole‐body glucose infusion during insulin, may caution against the use of isoenzyme‐5‐specific cyclic GMP phosphodiesterase inhibitors as therapeutic agents.

British Journal of Pharmacology (2003) 140, 1283–1291. doi:10.1038/sj.bjp.0705548
Rho kinase inhibitors block activation of pancreatic stellate cells
Authors: Masamune Atsushi , Kikuta Kazuhiro , Satoh Mashiro , Satoh Kennichi , Shimosegawa Tooru 
Published: November 2003

In response to pancreatic injury and in cell culture, pancreatic stellate cells (PSCs) are transformed (‘activated’) into highly proliferative myofibroblast‐like cells, which express α‐smooth muscle actin (α‐SMA), and produce type I collagen and other extracellular matrix components. There is accumulating evidence that activated PSCs play important roles in pancreatic fibrosis and inflammation.
The small GTP‐binding protein Rho has emerged as an important regulator of the actin cytoskeleton and cell morphology through the downstream effector Rho kinase (ROCK). But, the roles of Rho‐ROCK pathway in PSCs are unknown. Here, we examined the effects of (+)‐(R)‐trans‐4‐(1‐aminoethyl)‐N‐(4‐pyridyl) cyclohexanecarboxamide (Y‐27632) and HA‐1077 (fasudil), specific inhibitors of ROCK, on the activation of PSCs.
PSCs were isolated from the pancreas of male Wistar rats after perfusion with collagenase P. The actin cytoskeleton was analyzed by phalloidin staining. Expression of RhoA and ROCK was examined by immunostaining and Western blotting. Effects of Y‐27632 and HA‐1077 on α‐SMA expression, platelet‐derived growth factor‐induced proliferation and chemotaxis, and collagen production were assessed.
Culture‐activated PSCs developed a well‐spread cell shape, with extended stress fiber formation. PSCs expressed RhoA, ROCK‐1, and ROCK‐2.
Y‐27632 caused disassembly of stress fibers. Y‐27632 and HA‐1077 inhibited α‐SMA expression, proliferation, chemotaxis, and type I collagen production in culture‐activated PSCs.
In addition, Y‐27632 and HA‐1077 inhibited spontaneous activation of freshly isolated PSCs in culture on plastic.
These findings suggest a role of Rho‐ROCK pathway in the activation process of PSCs by regulating the actin cytoskeleton, and a potential application of Rho‐ROCK pathway inhibitors for the treatment of pancreatic inflammation and fibrosis.

British Journal of Pharmacology (2003) 140, 1292–1302. doi:10.1038/sj.bjp.0705551
Possible role of the protein kinase C/CPI‐17 pathway in the augmented contraction of human myometrium after gestation
Authors: Ozaki Hiroshi , Yasuda Katsuhiko , Kim Yoon‐Sun , Egawa Makoto , Kanzaki Hideharu , Nakazawa Hiroshi , Hori Masatoshi , Seto Minoru , Karaki Hideaki 
Published: November 2003

Activation of protein kinase C (PKC) by phorbol 12,13‐dibutylate (PDBu, 1 μM) induced sustained contractions with no increase in [Ca2+]i in nonpregnant and pregnant human myometria. The contractile effects of PDBu in pregnant myometrium were much greater than those in nonpregnant myometrium, and the contractions in pregnant myometrium were accompanied by an increase in myosin light chain (MLC) phosphorylation at Ser19.
The contraction induced by PDBu in pregnant myometrium was inhibited by the inhibitors of conventional PKC isoforms, bisindolylmaleimides and indolocarbazole, such as Go6976, Go6983, and Go6850 (1 μM). LY333531 (1 μM), a specific inhibitor of PKCβ, also inhibited the PDBu‐induced contraction in the pregnant myometrium.
In the pregnant myometrium permeabilized with α‐toxin, PDBu increased the contractions induced at fixed Ca2+ concentration (0.3 μM) both in nonpregnant and pregnant myometria, indicating Ca2+ sensitization of contractile elements.
Western immunoblot analysis indicated that pregnant myometrium contained PKC isozymes such as conventional PKC (α, β, γ), novel PKC (δ, ɛ, θ), and atypical PKC (ζ but not ι and λ). RT‐PCR and real‐time RT‐PCR analysis indicated that, among the conventional PKC, the levels of mRNA of β isoform in pregnant human myometrium were greater than those in nonpregnant myometrium.
CPI‐17 is a substrate for PKC, and the phosphorylated CPI‐17 is considered to inhibit myosin phosphatase. The levels of CPI‐17 mRNA and protein expression were also greater in the pregnant myometrium.
These results suggest that the PKC‐mediated contractile mechanism is augmented in human myometrium after gestation, and that this augmentation may be attributable to the increased activity of the β PKC isoform and CPI‐17.

British Journal of Pharmacology (2003) 140, 1303–1312. doi:10.1038/sj.bjp.0705552
Alkylglycerol opening of the blood–brain barrier to small and large fluorescence markers in normal and C6 glioma‐bearing rats and isolated rat brain capillaries
Authors: Erdlenbruch Bernhard , Alipour Mehrnaz , Fricker Gert , Miller David S , Kugler Wilfried , Eibl Hansjörg , Lakomek Max 
Published: November 2003

The blood–brain barrier (BBB) represents the major impediment to successful delivery of therapeutic agents to target tissue within the central nervous system. Intracarotid alkylglycerols have been shown to increase the transfer of chemotherapeutics across the BBB.
We investigated the spatial distribution of intracarotid fluorescein sodium and intravenous lissamine‐rhodamine B200 (RB 200)–albumin in the brain of normal and C6 glioma‐bearing rats after intracarotid co‐administration of 1‐O‐pentylglycerol (200 mM). To elucidate the mechanisms involved in the alkylglycerol‐mediated BBB opening, intraluminal accumulation of fluorescein isothiocyanate (FITC)–dextran 40,000 was studied in freshly isolated rat brain capillaries using confocal microscopy during incubation with different alkylglycerols. Furthermore, 1‐O‐pentylglycerol‐induced increase in delivery of methotrexate (MTX) to the brain was evaluated in nude mice.
Microscopic evaluation showed a marked 1‐O‐pentylglycerol‐induced extravasation of fluorescein and RB 200–albumin in the ipsilateral normal brain. In glioma‐bearing rats, increased tissue fluorescence was found in both tumor tissue and brain surrounding tumor. Confocal microscopy revealed a time‐ and concentration‐dependent accumulation of FITC–dextran 40,000 within the lumina of isolated rat brain capillaries during incubation with 1‐O‐pentylglycerol and 2‐O‐hexyldiglycerol, indicating enhanced paracellular transfer via tight junctions. Intracarotid co‐administration of MTX and 1‐O‐pentylglycerol (200 mM) in nude mice resulted in a significant increase in MTX concentrations in the ipsilateral brain as compared to controls without 1‐O‐pentylglycerol (P<0.005).
In conclusion, 1‐O‐pentylglycerol increases delivery of small and large compounds to normal brain and brain tumors and this effect is mediated at least in part by enhanced permeability of tight junctions.

British Journal of Pharmacology (2003) 140, 1201–1210. doi:10.1038/sj.bjp.0705554
Ouabain exerts biphasic effects on connexin functionality and expression in vascular smooth muscle cells
Authors: Martin Patricia E M , Hill Nathan S , Kristensen Bo , Errington Rachael J , Griffith Tudor M 
Published: November 2003

We have compared the effects of ouabain on the maintenance of gap junctional communication in rat aortic A7r5 smooth muscle cells, monkey COS‐1 fibroblasts and human HeLa epithelial cells.
Ouabain (1 mM) interrupted dye coupling between confluent A7r5 cells within ∼1 h, and high concentrations of ouabain were similarly required to reduce coupling between COS‐1 cells selected to express the rat α1 Na+/K+‐ATPase subunit, which is ouabain resistant. By contrast, low concentrations of ouabain (1–10 μM) attenuated dye transfer in wild‐type COS‐1 and HeLa cells, whose endogenous α1 subunits possess relatively high affinity for the glycoside (Ki∼0.3 vs ∼100 μM) Ouabain‐induced reductions in dye transfer therefore correlated with the ability of the glycoside to bind to the Na+/K+‐ATPase isoenzymes expressed in these different cell lines.
No consistent relationship between inhibition of intercellular dye transfer and secondary changes in [Ca2+]i or pHi could be identified following incubation with ouabain.
In separate experiments, the effects of ouabain on real‐time trafficking of connexin protein were monitored by time‐lapse microscopy of A7r5 cells transfected to express a fluorescent Cx43‐green fluorescent protein (GFP) and the ability of the glycoside to modulate endogenous expression of connexins (Cx) 40 and 43 evaluated in A7r5 cells by immunochemical and Western blot analysis.
Ouabain (1 mM) depressed vesicular trafficking of Cx43‐GFP after ∼1 h, and caused a time‐dependent loss of endogenous Cx40 and Cx43 protein that was first evident at 2 h and almost complete after 4 h. These effects of ouabain on Cx expression were reversed ∼90 min following washout of the glycoside.
We conclude that ouabain exerts biphasic effects on the intercellular communication that involve an initial decrease in gap junctional permeability followed by a global reduction in the expression of Cx protein. Further studies are necessary to establish to what extent these actions of ouabain reflect inversion of the normal [Na+]i/[K+]i ratio and/or conversion of the Na+/K+‐ATPase into a general signal transducer that regulates downstream protein synthesis.

British Journal of Pharmacology (2003) 140, 1261–1271. doi:10.1038/sj.bjp.0705556
IL‐13 enhances agonist‐evoked calcium signals and contractile responses in airway smooth muscle
Authors: Tliba Omar , Deshpande Deepak , Chen Hang , Van Besien Christopher , Kannan Mathur , Panettieri Reynold A , Amrani Yassine 
Published: November 2003

Growing evidence suggests that interleukin (IL)‐13, a Th2‐type cytokine, plays a critical role in the development of bronchial hyper‐responsiveness (BHR), an essential feature of asthma, although the underlying mechanisms remain unknown. In the present study, we investigated whether IL‐13 directly affects airway smooth muscle (ASM) function. In murine tracheal rings, IL‐13 (100 ng ml−1, 24 h) significantly increased both the carbachol‐ and KCl‐induced maximal force generation without affecting ASM sensitivity. In cultured human ASM cells, IL‐13 (50 ng ml−1, 24 h) also augmented cytosolic calcium levels to bradykinin, histamine and carbachol by 60, 35 and 26%, respectively. The present study demonstrates that IL‐13 may promote BHR by directly modulating ASM contractility, an effect that may be due to enhanced G protein‐coupled receptor (GPCR)‐associated calcium signaling.British Journal of Pharmacology (2003) 140, 1159–1162. doi:10.1038/sj.bjp.0705558
Verotoxin activates mitogen‐activated protein kinase in human peripheral blood monocytes: role in apoptosis and proinflammatory cytokine release
Authors: Cameron Pamela , Smith Susan J , Giembycz Mark A , Rotondo Dino , Plevin Robin 
Published: November 2003

In this study, we examined the role of mitogen‐activated protein (MAP) kinases in the effects of verotoxins (VTs), from Escherichia coli O157:H7, upon both apoptosis and the release of tumour necrosis factor alpha (TNF‐α) and granulocyte–macrophage colony‐stimulated factor (GM‐CSF) from human monocytes.
Both VT1 and VT2 stimulated a weak, transient increase in c‐Jun‐N‐terminal kinase (JNK) activity and a strong activation of both p38 mitogen‐activated protein kinase (MAP kinase) and extracellular‐regulated kinase (ERK) activity in human monocytes, which was sustained in the case of p38 MAP kinase.
Stimulation of human monocytes with VT2 (100 ng ml−1) did not result in an increase in apoptosis; however, the toxin stimulated the release of both TNF‐α and GM‐CSF.
Pretreatment of human monocytes with the p38 MAP kinase inhibitor SB203580, at concentrations from 100 nM to 10 μM, significantly decreased the VT1‐ and VT2‐induced TNF‐α and GM‐CSF release from monocytes. In contrast, inhibition of MEK1 with PD98059 only significantly decreased GM‐CSF release.
Pretreatment of monocytes with SP600125 inhibited both GM‐CSF and TNF‐α production; however, significant effects upon p38 MAP kinase and ERK activation were observed.
Taken together, these results suggest a role for p38 MAP kinase and ERK in cytokine generation in response to the verotoxins. A role for JNK remains undetermined.

British Journal of Pharmacology (2003) 140, 1320–1330. doi:10.1038/sj.bjp.0705560
Characterisation of marrubenol, a diterpene extracted from Marrubium vulgare, as an L‐type calcium channel blocker
Authors: El Bardai Sanae , Wibo Maurice , Hamaide Marie‐Christine , Lyoussi Badiaa , Quetin‐Leclercq Joëlle , Morel Nicole 
Published: November 2003

The objective of the present study was to investigate the mechanism of the relaxant activity of marrubenol, a diterpenoid extracted from Marrubium vulgare. In rat aorta, marrubenol was a more potent inhibitor of the contraction evoked by 100 mM KCl (IC50: 11.8±0.3 μM, maximum relaxation: 93±0.6%) than of the contraction evoked by noradrenaline (maximum relaxation: 30±1.5%).
In fura‐2‐loaded aorta, marrubenol simultaneously inhibited the Ca2+ signal and the contraction evoked by 100 mM KCl, and decreased the quenching rate of fura‐2 fluorescence by Mn2+.
Patch‐clamp data obtained in aortic smooth muscle cells (A7r5) indicated that marrubenol inhibited Ba2+ inward current in a voltage‐dependent manner (KD: 8±2 and 40±6 μM at holding potentials of −50 and −100 mV, respectively).
These results showed that marrubenol inhibits smooth muscle contraction by blocking L‐type calcium channels.

British Journal of Pharmacology (2003) 140, 1211–1216. doi:10.1038/sj.bjp.0705561
Docosahexaenoic acid and other fatty acids induce a decrease in pHi in Jurkat T‐cells
Authors: Aires Virginie , Hichami Aziz , Moutairou Kabirou , Khan Naim Akhtar 
Published: November 2003

Docosahexaenoic acid (DHA) induced rapid (t1/2=33 s) and dose‐dependent decreases in pHi in BCECF‐loaded human (Jurkat) T‐cells. Addition of 5‐(N,N‐dimethyl)‐amiloride, an inhibitor of Na+/H+ exchanger, prolonged DHA‐induced acidification as a function of time, indicating that the exchanger is implicated in pHi recovery.
Other fatty acids like oleic acid, arachidonic acid, eicosapentaenoic acid, but not palmitic acid, also induced a fall in pHi in these cells.
To assess the role of calcium in the DHA‐induced acidification, we conducted experiments in Ca2+‐free (0% Ca2+) and Ca2+‐containing (100% Ca2+) buffer. We observed that there was no difference in the degree of DHA‐induced transient acidification in both the experimental conditions, though pHi recovery was faster in 0% Ca2+ medium than that in 100% Ca2+ medium.
In the presence of BAPTA, a calcium chelator, a rapid recovery of DHA‐induced acidosis was observed. Furthermore, addition of CaCl2 into 0% Ca2+ medium curtailed DHA‐evoked rapid pHi recovery. In 0% Ca2+ medium, containing BAPTA, DHA did not evoke increases in [Ca2+]i, though this fatty acid still induced a rapid acidification in these cells. These observations suggest that calcium is implicated in the long‐lasting DHA‐induced acidosis.
DHA‐induced rapid acidification may be due to its deprotonation in the plasma membrane (flip‐flop model), as suggested by the following observations: (1) DHA with a –COOH group induced intracellular acidification, but this fatty acid with a –COOCH3 group failed to do so, and (2) DHA, but not propionic acid, ‐induced acidification was completely reversed by addition of fatty acid‐free bovine serum albumin in these cells.
These results suggest that DHA induces acidosis via deprotonation and Ca2+ mobilization in human T‐cells.

British Journal of Pharmacology (2003) 140, 1217–1226. doi:10.1038/sj.bjp.0705563
Protein aggregation in motor neurone disorders
Authors: Wood J. D. , Beaujeux T. P. , Shaw P. J. 
Published: November 2003

Toxicity associated with abnormal protein folding and protein aggregation are major hypotheses for neurodegeneration. This article comparatively reviews the experimental and human tissue‐based evidence for the involvement of such mechanisms in neuronal death associated with the motor system disorders of X‐linked spinobulbar muscular atrophy (SBMA; Kennedy's disease) and amyotrophic lateral sclerosis (ALS), especially disease related to mutations in the superoxide dismutase (SOD1) gene.Evidence from transgenic mouse, Drosophila and cell culture models of SBMA, in common with other trinucleotide repeat expansion disorders, show protein aggregation of the mutated androgen receptor, and intraneuronal accumulation of aggregated protein, to be obligate mechanisms. Strong experimental data link these phenomena with downstream biochemical events involving gene transcription pathways (CREB‐binding protein) and interactions with protein chaperone systems. Manipulations of these pathways are already established in experimental systems of trinucleotide repeat disorders as potential beneficial targets for therapeutic activity.In contrast, the evidence for the role of protein aggregation in models of SOD1‐linked familial ALS is less clear‐cut. Several classes of intraneuronal inclusion body have been described, some of which are invariably present. However, the lack of understanding of the biochemical basis of the most frequent inclusion in sporadic ALS, the ubiquitinated inclusion, has hampered research. The toxicity associated with expression of mutant SOD1 has been intensively studied however. Abnormal protein aggregation and folding is the only one of the four major hypotheses for the mechanism of neuronal degeneration in this disorder currently under investigation (the others comprise oxidative stress, axonal transport and cytoskeletal dysfunctions, and glutamatergic excitotoxicity). Whilst hyaline inclusions, which are strongly immunoreactive to SOD1, are linked to degeneration in SOD1 mutant mouse models, the evidence from human tissue is less consistent and convincing. A role for mutant SOD1 aggregation in the mitochondrial dysfunction associated with ALS, and in potentially toxic interactions with heat shock proteins, both leading to apoptosis, are supported by some experimental data. Direct in vitro data on mutant SOD1 show evidence for spontaneous oligomerization, but the role of such oligomers remains to be elucidated, and therapeutic strategies are less well developed for this familial variant of ALS.
Blood protein polymorphisms in native chicken breeds in Yunnan province of China
Authors: OKAMOTO Shin , INAFUKU Keiichiro , TING Zhu , MAEDA Yoshizane , HOU Dexing , TAMG Yang Feng , YUN Zhang Han , XU Wenbo , SHI Liming , HASHIGUCHI Tsutomu 
Published: November 2003

ABSTRACTBlood samples were collected from four native breeds (Chahua chicken, Xishuangbanna Game chicken, Wuding chicken, and Yangbi Huang chicken) in the Yunnan province of China, and their protein polymorphisms were analyzed by using electrophoresies. Out of 16 loci examined, polymorphisms were found in the following eight loci: plasma esterase, plasma amylase, plasma alkaline phosphatase, plasma albumin, plasma transferrin, plasma postalbumin, and hemoglobin. The other eight loci, erythrocyte lactate dehydrogenase, erythrocyte 6‐phosphogluconate dehydrogenase, erythrocyte phosphoglucomutase, erythrocyte phosphohexose isomerase, erythrocyte tetrazolium oxidase, erythrocyte malate dehydrogenase, erythrocyte esterase and hemoglobin, were monomorphic. The proportion of the polymorphic loci and the expected average heterozygosity were estimated as 0.438–0.500 and 0.141–0.174, respectively. A dendrogram was drawn according to the genetic distance, which was calculated by the Nei's genetic distance matrix, among four Chinese native breeds. The results indicated that Chahua, Wuding and Yangbi Huang chickens were genetically remote from Xishuangbanna Game chicken. Moreover, the genetic distance was calculated among the Sri Lankan, Bangladeshi and Nepalese native fowl populations, and another dendrogram was constructed. In the latter dendrogram, Chahua, Wuding and Yangbi Huang chickens were genetically closer to Sri Lankan and Bangladeshi native fowls than Xishuangbanna Game chicken.
Number of nitrate‐ and nitrite‐reducing Selenomonas ruminantium in the rumen, and possible factors affecting its growth
Authors: YOSHII Takahiro , ASANUMA Narito , HINO Tsuneo 
Published: November 2003

ABSTRACTThe cell number of Selenomonas ruminantium (S. ruminantium) that reduces nitrate and nitrite in the rumen was usually 8–10% of the total number of S. ruminantium (an order of 106/mL). The percentage was not affected by the roughage/concentrate ratio or nitrate content of the diet in 2 weeks. However, feeding a high‐nitrate diet for 12 weeks increased the percentage. The percentage of lactate‐using S. ruminantium, such as the ssp. lactilytica, was less than 1% of the total number of S. ruminantium. No S. ruminantium was found that used formate as an electron donor for nitrate and nitrite reduction. Lactate and H2 appeared to be important for nitrate and nitrite reduction by S. ruminantium. Nitrate reduction by S. ruminantium was enhanced by the coexistence of amylolytic bacteria in a medium containing starch, and as a result, nitrite accumulation increased. Coexistence of cellulolytic bacteria facilitated the growth of S. ruminantium in a medium containing cellulose, and consequently increased nitrite reduction. In order to suppress nitrite accumulation in the rumen, it may be important to enhance fiber digestion.