bluuebunny/crossref_metadata_2025 huggingface dataset:
Role of leukemia inhibitor factor (LIF) in decidualisation of murine uterine stromal cells in vitro
Authors: Fouladi Nashta AA , Andreu CV , Nijjar N , Heath JK , Kimber SJ
Published: December 2004

Decidualisation of uterine stromal cells is a prerequisite for implantation of the embryo in mice. Here we have used an in vitro culture system in which stromal cells decidualise as indicated by a number of markers, including an increase in alkaline phosphatase (ALP) activity. The latter was used as a quantitative marker of decidualisation in the presence of low (2%) fetal calf serum. Prostaglandin E(2) (PGE(2)), which is known to induce decidualisation, increased ALP activity, and this effect was blocked in a dose-dependent manner by indomethacin. Leukemia inhibitory factor (LIF) was then examined, but it had no effect on PGE(2) secretion. However, LIF suppressed ALP activity in a dose-dependent manner in the presence of 2% serum, while an inhibitor of LIF that competes for binding to its receptor reversed the effect of LIF and increased ALP activity above the control level. In serum-free cultures, stromal cells differentiated rapidly, and no differences were observed between LIF-treated and untreated cultures. Stromal cells produce LIF during in vitro culture, and this peaked at 48 h. Freshly collected stromal cells from both day-2 and -4 pregnant mice expressed mRNA for the LIF receptor, and the transcript level was higher in cells isolated on day 4. However, no differences were observed in the relative levels of transcripts in cells from day 2 and day 4 after culture, nor were there differences between the LIF-treated cultures and controls. Therefore, in this study, we have shown that LIF suppresses decidualisation of murine uterine stromal cells in the presence of serum, this is not due to the regulation of PGE(2) secretion by stromal cells.
Regulation of phosphate (Pi) transport and NaPi-III transporter (Pit-1) mRNA in rat osteoblasts
Authors: Zoidis E , Ghirlanda-Keller C , Gosteli-Peter M , Zapf J , Schmid C
Published: December 2004

In osteoblasts only the type III Na(+)-dependent phosphate (NaPi) transporter isoforms Pit-1 and Pit-2 have been identified. We tested the effects of extracellular Pi, Ca(2+) and IGF-I on Na(d)Pi transport and Pit-1 or Pit-2 mRNA expression in rat osteoblastic (PyMS) cells. The v(max) of Na(d)Pi transport was higher in cells kept in Pi-free, serum-free medium for 24 h than in controls at 1 mM Pi (2.47+/-0.20 vs 1.83+/-0.17 nmol/mg protein x 10 min). The apparent affinity constant (K(M)) for Pi remained unchanged. Pi withdrawal for 24 h did not impair cell viability whereas increasing the extracellular Pi to 5 mM resulted in cell death. Pit-1 (but not Pit-2) mRNA was upregulated following Pi deprivation, Ca(2+) treatment or after treatment with 1 nM IGF-I, known to stimulate Na(d)Pi transport and cell proliferation. IGF-I also stimulated Na(d)Pi transport and Pit-1 mRNA in primary rat calvarial osteoblasts. Expression of Pit-1 mRNA in vivo and the coordinate regulation of Pit-1 mRNA and Pi transport in osteoblastic cells suggest that Pit-1 is a candidate transporter of physiological relevance in bone.
Macrophage migration inhibitory factor: molecular, cellular and genetic aspects of a key neuroendocrine molecule
Authors: Donn RP , Ray DW
Published: December 2004

The immunological and neuroendocrine properties of macrophage migration inhibitory factor (MIF) are diverse. In this article we review the known cellular, molecular and genetic properties of MIF that place it as a key regulatory cytokine, acting within both the innate and adaptive immune responses.The unexpected and paradoxical induction of MIF secretion by low concentrations of glucocorticoids is explored. The role of MIF as a locally acting modulator of glucocorticoid sensitivity within foci of inflammation is also discussed. MIF has no homology with any other pro-inflammatory cytokine and until recently lacked a recognised transmembrane receptor. MIF has also been shown to be directly taken up into target cells and to interact with intracellular signalling molecules, including the Jun activation domain-binding protein Jab-1.Comprehensive analysis of the MIF gene has identified important functional polymorphisms and a series of genetic studies has revealed both association and linkage of MIF with inflammatory diseases. Altered MIF regulation may therefore be pivotal to acquiring chronic inflammation following an innate immune response.
Kinetic studies and production rate of equine (e) FSH in ovariectomized pony mares. Application to the determination of a dosage regimen for eFSH in a superovulation treatment
Authors: Briant C , Toutain PL , Ottogalli M , Magallon T , Guillaume D
Published: December 2004

The appropriate dosage regimen for equine FSH (eFSH) (dose, dosing interval) administration in a superovulation treatment in pony mares was determined by a kinetic approach using production rates and kinetic parameters of elimination of the hormone. Two dosage regimens were then tested in superovulation protocols. The eFSH production rates were determined by sampling four ovariectomized pony mares every 10 min for 8 h during the breeding season. Kinetic parameters were determined by administering four dose levels of a preparation of eFSH (4.4, 8.8, 17.6 and 35.2 micro g/kg) by the i.v. route to the same mares, in a randomized 4x4 Latin Square protocol. The overall mean plasma clearance was 0.256+/- 0.07 ml.kg(-1).min(-1), and was independent of the dose. The mean residence time ranged from 5.5 to 10.8 h and increased with the dose. The estimated FSH production rates were 8.6 to 15.3 micro g.kg(-1).day(-1) (i.e. 2.89 to 3.45 mg per day per mare). Two dosage regimens of eFSH were then tested in cyclic mares (ten treated mares in each trial): 3.45 mg per day (4.4 micro g/kg three times a day by the i.v. route), which corresponds to the maximal daily production rate of the native hormone in ovariectomized mares, and 1.72 mg per day (2.2 micro g/kg three times a day), which corresponds to half of that production rate. The dosage regimen of 2.2 micro g/kg three times a day gave satisfactory results in terms of efficacy (numbers of ovulations and embryos) with minimal unwanted effects (luteinized or anovulatory follicles).
Characterization of the concentration gradient of prostaglandin H synthase 2 mRNA throughout the pregnant baboon uterus
Authors: Wu WX , Smith GC , Rose J , Nathanielsz PW
Published: December 2004

The present study was designed to determine the effect of the spatial gradient from the cervix to the uterine fundus on the control of local prostaglandin H synthase (PGHS) 2 mRNA expression. We performed total cesarean hysterectomies during the last trimester in 12 pregnant baboons, 7 not in labor and 5 in labor, and examined PGHS2 mRNA expression throughout the uterus. PGHS2 mRNA abundance was quantified by in situ hybridization and northern blot analysis in the uterine fundus, lower uterine segment and the different segments of the cervix. Quantitative northern blot and in situ analysis demonstrated a gradient of PGHS2 mRNA expression, with the highest levels at the level of the lower portion of the cervix and decreased expression through the mid- and upper portion of the cervix and lower uterine segment; the lowest levels of expression were seen in the uterine fundus. Moreover, cellular localization of PGHS2 mRNA and protein demonstrated high levels of expression in the cervical glandular epithelial cells with only occasional staining of smooth muscle cells in pregnant baboons. Decreased PGHS2 mRNA concentration gradient from the cervical external os to the fundus suggests that prostaglandin (PG) production in the uterus and cervix strongly depends on anatomical relations. This increased local PG production activity may be critical to pregnancy-associated lower uterine segment elongation, cervical softening and effacement in primate labor. These data provide a compelling biological basis for the use of PGHS2 inhibitors in the prophylaxis of preterm birth and cervical incompetence.
Testicular endocrine activity is upregulated by D-aspartic acid in the green frog, Rana esculenta
Authors: Raucci F , Assisi L , D'Aniello S , Spinelli P , Botte V , Di Fiore MM
Published: December 2004

This study investigated the involvement of D-aspartic acid (D-Asp) in testicular steroidogenesis of the green frog Rana esculenta and its effect on stimulation of thumb pad morphology and glandular activity, a typical testosterone-dependent secondary sexual characteristic in this amphibian species. In the testis, D-Asp concentrations vary significantly during the reproductive cycle: they are low in pre- and post-reproductive periods, but reach peak levels in the reproductive period (140-236 nmol/g wet tissue). Moreover, the concentrations of D-Asp in the testis through the sexual cycle positively match the testosterone levels in the gonad and the plasma. The racemase activity evaluated during the cycle expresses its peak when D-Asp and testosterone levels are highest, that is, during the reproductive period, confirming the synthesis of D-Asp from L-Asp by an aspartate racemase. Short-term in vivo experiments consisting of a single injection of D-Asp (2.0 micro mol/g body weight) demonstrated that this amino acid accumulates significantly in the testis, and after 3 h its uptake is coupled with a testosterone increase in both testis and plasma. Moreover, within 18 h of amino acid administration, the D-Asp concentration in the testis decreased along with the testosterone titer to prestimulation levels. Other amino acids (L-Asp, D-Glu and L-Glu) used instead of D-Asp were ineffective, confirming that the significant increase in testicular testosterone was a specific feature of this amino acid. In long-term experiments, D-Asp had been administered chronically to frogs caught during the three phases of the reproductive cycle, inducing testosterone increase and 17beta-estradiol decrease in the gonad during the pre- and post-reproductive period, and vice versa during the reproductive period. The stimulatory effect of D-Asp on testosterone production by the testis is consistent with the stimulation of spermatogenesis and the maturation of thumb pads occurring in D-Asp-treated frogs. In these last animals, there was an increase of seminiferous ampoule area and a higher number of spermatids and sperm. Moreover, in spermatogonia I and II and in spermatocytes, a proliferating cell nuclear antigen (PCNA) intense immunopositivity was observed. In addition, the thumb pads of D-Asp-treated frogs compared with controls showed a significantly thicker epithelial lining, a wider area of their glands with taller secretion cells, and more numerous, PAS-positive-rich secretions. Finally, these results provide functional evidence for a biologic role of D-Asp in amphibian male steroidogenesis; therefore, this unusual amino acid could be considered a modulatory agent for reproductive processes.
Influence of genotype on the differential ontogeny of uncoupling protein 2 and 3 in subcutaneous adipose tissue and muscle in neonatal pigs
Authors: Mostyn A , Litten J C , Perkins K S , Alves-Guerra M C , Pecqueur C , Miroux B , Symonds M E , Clarke L
Published: December 2004

The present study aimed to determine whether porcine genotype and/or postnatal age influenced mRNA abundance or protein expression of uncoupling protein (UCP)2 or 3 in subcutaneous adipose tissue (AT) and skeletal muscle (SM) and the extent to which these differences are associated with breed-specific discordance in endocrine and metabolic profiles. Piglets from commercial and Meishan litters were ranked according to birth weight. Tissue samples were obtained from the three median piglets from each litter on either day 0, 4, 7, 14 or 21 of neonatal life. UCP2 protein abundance in AT was similar between genotypes on the first day of life, but it was elevated at all subsequent postnatal ages (P<0.05) in AT of Meishan piglets. In contrast, UCP2 mRNA abundance was lower in Meishans up to 14 days of age. UCP2 mRNA expression was not correlated with protein abundance in either breed at any age. UCP3 mRNA in AT was similar between breeds up to day 7; thereafter, expression was higher (general linear model, P<0.05) in Meishan piglets. Conversely, UCP3 mRNA expression in SM was higher in commercial piglets after day 7. Colonic temperature remained lower in Meishan than commercial piglets throughout the study; this was most obvious in the immediate post-partum period when Meishan piglets had lower (P<0.05) plasma triiodothyronine. In conclusion, we have demonstrated that porcine genotype influences the expression and abundance of UCP2 and 3, an influence which may, in part, be due to the distinctive endocrine profiles associated with each genotype.
High glucose potentiates cytokine- and streptozotocin-induced apoptosis of rat islet cells: effect on apoptosis-related genes
Authors: Mellado-Gil J M , Aguilar-Diosdado M
Published: December 2004

Pancreatic β-cell apoptosis is known to participate in the β-cell destruction process that occurs in diabetes. A better understanding of how it takes place is essential for future development of therapeutic strategies aimed at preventing β-cell loss and diabetes. In this study we determine the possible role that high glucose concentration might play as an enhancer of cytokine- and streptozotocin (STZ)-mediated rat islet cell apoptosis in vitro and its relationship with potential changes in the expression of pro- and anti-apoptotic proteins. Rat islets treated with a cytokine combination (interleukin (IL)-1β, tumor necrosis factor (TNF)-α and interferon (IFN)-γ) displayed a significant increase in islet cell apoptosis when the islets were incubated in 24.4 mM glucose compared with untreated islets at the same glucose concentration (13.07 ± 1.78% vs 6.09 ± 0.78%; P < 0.01) or islets incubated in 5.5 mM glucose concentration and cytokines (13.07 ± 1.78% vs 8.04 ± 1.56%; P < 0.05). IL-1β alone did not induce a significant increase in the apoptotic rates in islet cells cultured at normal or high glucose concentrations. STZ significantly increased islet cell apoptosis when islets were cultured in 24.4 mM glucose concentration compared with untreated islets at the same glucose concentration (6.02 ± 0.62% vs 4.44 ± 0.63%; P < 0.05). High glucose induced an increase in Fas expression in the islet cells, and this increase was maintained after cytokine or STZ treatment. However, the expression of anti-apoptotic mediators such as bcl-2 and bcl-xL did not show any significant change. These results suggest that cytokine- and STZ-mediated apoptotic effects on islet cells might be mediated by a glucose-induced hyperfunctional status and associated with an increase in Fas (Apo-1, CD-95) expression and no changes in the expression of the anti-apoptotic proteins bcl-xL and bcl-2.
Overexpression of short heterodimer partner recovers impaired glucose-stimulated insulin secretion of pancreatic β-cells overexpressing UCP2
Authors: Suh Y-H , Kim S-Y , Lee H-Y , Jang B C , Bae J H , Sohn J-N , Bae J-H , Suh S-I , Park J-W , Lee K-U , Song D-K
Published: December 2004

The short heterodimer partner (SHP) (NR0B2) is an orphan nuclear receptor whose function in pancreatic β-cells is unclear. Mitochondrial uncoupling protein (UCP2) in β-cells is upregulated in obesity-related diabetes, causing impaired glucose-stimulated insulin secretion (GSIS). We investigated whether SHP plays a role in UCP2-induced GSIS impairment. We overexpressed SHP in normal islet cells and in islet cells overexpressing UCP2 by an adenovirus-mediated infection technique. We found that SHP overexpression enhanced GSIS in normal islets, and restored GSIS in UCP2-overexpressing islets. SHP overexpression increased the glucose sensitivity of ATP-sensitive K+ (KATP) channels and enhanced theATP/ADP ratio. A peroxisome proliferator-activated receptor gamma (PPARγ) antagonist, GW9662, did not block the SHP effect on GSIS. SHP overexpression also corrected the impaired sensitivity of UCP2-overexpressing β-cells to methylpyruvate, another energy fuel that bypasses glycolysis and directly enters the Krebs cycle. KATP channel inhibition mediated by dihydroxyacetone, which gives reducing equivalents directly to complex II of the electron transport system, was similar in Ad-Null-, Ad-UCP2- and Ad-UCP2+Ad-SHP-infected cells. The mitochondrial metabolic inhibitor sodium azide totally blocked the effect of SHP overexpression on GSIS. These results suggest that SHP positively regulates GSIS in β-cells and restores glucose sensitivity in UCP2-overexpressing β-cells by enhancing mitochondrial glucose metabolism, independent of PPARγ activation.
Rosiglitazone impacts negatively on bone by promoting osteoblast/osteocyte apoptosis
Authors: Sorocéanu M Alexandra , Miao Dengshun , Bai Xiu-Ying , Su Hanyi , Goltzman David , Karaplis Andrew C
Published: December 2004

Thiazolidinediones (TZDs) increase peripheral tissue insulin sensitivity in patients with type 2 diabetes mellitus by activating the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ). In bone marrow stromal cell cultures and in vivo, activation of PPARγ by high doses (20 mg/kg/day) of TZDs has been reported to alter stem cell differentiation by promoting commitment of progenitor cells to the adipocytic lineage while inhibiting osteoblastogenesis. Here, we have examined the in vivo effects of low-dose rosiglitazone (3 mg/kg/day) on bone, administered to mice by gavage for 90 days. Rosiglitazone-treated mice had increased weight when compared with controls, with no significant alterations in serum levels of glucose, calcium or parathyroid hormone (PTH). Bone mineral density (BMD) at the lumbar vertebrae (L1–L4), ilium/sacrum, and total body was diminished by rosiglitazone treatment. Histologically, bone was characterized by decreased trabecular bone volume and increased marrow space with no significant change in bone marrow adipocity. Decreased osteoblast number and activity due to increased apoptotic death of osteoblasts and osteocytes was apparent while osteoclast parameters and serum levels of osteocalcin, alkaline phosphatase activity, and leptin were unaltered by rosiglitazone treatment. Therefore, the imbalance in bone remodeling that follows rosiglitazone administration arises from increased apoptotic death of osteogenic cells and diminished bone formation leading to the observed decrease in trabecular bone volume and BMD. These novel in vivo effects of TZDs on bone are of clinical relevance as patients with type 2 diabetes mellitus and other insulin resistant states treated with these agents may potentially be at increased risk of osteoporosis.
Growth hormone-induced blood pressure decrease is associated with increased mRNA levels of the vascular smooth muscle KATP channel
Authors: Tivesten Åsa , Barlind Anna , Caidahl Kenneth , Klintland Natalia , Cittadini Antonio , Ohlsson Claes , Isgaard Jörgen
Published: December 2004

Growth hormone (GH) deficiency is associated with abnormal vascular reactivity and development of atherosclerosis. GH treatment in GH deficient states restores systemic vascular resistance, arterial compliance, endothelium-dependent and endothelium-independent vasodilation, and may reverse markers of early atherosclerosis. However, very little is known about the molecular mechanisms underlying these effects. In the present study, male Sprague Dawley rats were hypophysectomized and treated for two weeks with GH (recombinant human GH, 2 mg/kg/day) or saline as s.c. injections twice daily. GH decreased aortic systolic blood pressure compared with saline-treated animals, while the diastolic blood pressure was not significantly changed. GH treatment increased cardiac output as determined by Doppler-echocardiography and the calculated systemic vascular resistance was markedly reduced. In order to identify GH-regulated genes of importance for vascular function, aortic mRNA levels were analyzed by the microarray technique and correlated to the systolic blood pressure levels. Using this approach, we identified 18 GH-regulated genes with possible impact on vascular tone and atherogenesis. In particular, mRNA levels of the inwardly rectifying potassium channel Kir6.1 and the sulfonylurea receptor 2B, which together form the vascular smooth muscle ATP-sensitive potassium channel, were both up-regulated by GH treatment and highly correlated to systolic blood pressure. Our findings establish a major role for GH in the regulation of vascular physiology and gene expression. Increased expression of the ATP-sensitive potassium channel, recently shown to be crucial in the regulation of vascular tone, constitutes a possible mechanism by which GH governs vascular tone.
Gene expression and protein localisation for activin-A, follistatin and activin receptors in goat ovaries
Authors: Silva J R V , van den Hurk R , van Tol H T A , Roelen B A J , Figueiredo J R
Published: December 2004

We studied the protein and mRNA expression of activin-A, follistatin and activin receptors in goat ovaries to find evidence of their possible role in ovarian activity, particularly in the various stages of follicle development. Ovaries of cyclic goats were collected and then either fixed in paraformaldehyde for immunohistochemical localisation of activin-A, follistatin, activin receptors IIA/B (ActR-IIA/B) and IA (ActR-IA) proteins or used to obtain samples to demonstrate mRNA expression of activin-A (βA subunit), follistatin, ActR-IIA, -IIB, -IA and -IB, using RT-PCR. For this latter goal, primordial, primary and secondary follicles were isolated mechanically, washed to remove the stromal cells and then used for RT-PCR. In addition, oocytes, cumulus, mural granulosa and theca cells from small (<3 mm) and large (3–6 mm) antral follicles, luteal cells and surface epithelium were collected to study mRNA expression. Activin-A and follistatin proteins were found in oocytes of all follicle classes, granulosa cells from the primary follicle stage onwards, theca cells of antral follicles, corpora lutea and ovarian surface epithelium. In antral follicles, these proteins were detected both in cumulus and mural granulosa cells. ActR-IIA/B protein was found at the same follicular sites, and also in granulosa cells of primordial follicles onward. The localisation of ActR-IA corresponded with that of ActR-IIA/B, but the former protein was absent in the theca of large antral follicles. The mRNAs for activin-A (βA subunit), follistatin, and ActR-IIA, -IIB, -IA and -IB were detected at all follicular and cellular types studied, except that ActR-IIB was not found in follicles that had not developed an antrum yet. In conclusion, in goat ovaries, transcripts of activin-A (βA subunit), its receptors and its binding protein follistatin are expressed and their proteins formed at all follicular stages and in corpora lutea. These findings indicate a role of activin-A in the local regulatory system during the entire follicular development and during luteal activity.
Evidence that lactotrophs do not differentiate directly from somatotrophs during chick embryonic development
Authors: Fu Xiaoqin , Nishimura Shotaro , Porter Tom E
Published: December 2004

It is generally accepted that, in mammals, lactotrophs differentiate from somatotrophs through an intermediate cell type, the mammosomatotroph. However, little information exists about mammosomatotrophs and their relationship with lactotroph development in non-mammalian vertebrates. We reported previously that corticosterone (CORT) can induce both somatotroph and lactotroph differentiation in cultures of chicken embryonic pituitary cells. Our current objectives were to determine the abundance of mammosomatotrophs during chicken pituitary development, to identify mammosomatotrophs during CORT induction of lactotrophs, and to explore whether lactotrophs induced by CORT are derived from somatotrophs. Cells that produced prolactin (PRL) only, growth hormone (GH) only or both hormones simultaneously were detected by three approaches – dual immunofluorescence, a combination of immunofluorescence and immunocytochemistry (ICC), and by ICC using combinations of antibodies to GH and PRL. Mammosomatotrophs were not detected between embryonic day (E) 16 and E20, even though lactotrophs increased from nearly absent to greater than 10% of all pituitary cells during this period. CORT induced more than 10% of all E13 pituitary cells to produce PRL, while the percentage of mammosomatotrophs remained at less than 1% of all cells. When cells from the cephalic and caudal lobes of the anterior pituitary were treated separately, CORT increased GH cells in cultures from the caudal lobe. No PRL cells were found in the caudal lobe. In the cephalic lobe, CORT increased lactotrophs, while GH cells were barely detected. In summary, mammosomatotrophs are rare during chicken pituitary development, and CORT does not induce lactotrophs from somatotrophs. These findings indicate that, unlike in mammals, lactotrophs do not differentiate from somatotrophs during chicken embryonic development.
Characterization of the resistance to the anorectic and endocrine effects of leptin in obesity-prone and obesity-resistant rats fed a high-fat diet
Authors: Tulipano G , Vergoni A V , Soldi D , Muller E E , Cocchi D
Published: December 2004

Leptin produced by adipocytes controls body weight by restraining food intake and enhancing energy expenditure at the hypothalamic level. The diet-induced increase in fat mass is associated with the presence of elevated circulating leptin levels, suggesting the development of resistance to its anorectic effect. Rats, like humans, show different susceptibility to diet-induced obesity. The aim of the present study was to compare the degree of leptin resistance in obesity-prone (OP) vs obesity-resistant (OR) rats on a moderate high-fat (HF) diet and to establish if the effects of leptin on hypothalamo–pituitary endocrine functions were preserved. Starting from 6 weeks after birth, male Sprague–Dawley rats were fed on either a commercial HF diet (fat content: 20% of total calorie intake) or a standard pellet chow (CONT diet, fat content: 3%). After 12 weeks of diet, rats fed on HF diet were significantly heavier than rats fed on CONT diet. Animals fed on HF diet were ranked according to body weight; the two tails of the distribution were called OP and OR rats respectively. A polyethylene cannula was implanted into the right ventricle of rats 1 week before central leptin administration. After 12 weeks of HF feeding, both OR and OP rats were resistant to central leptin administration (10 μg, i.c.v.) (24 h calorie intake as a percent of vehicle-treated rats: CONT rats, 62 [50; 78]; OR, 93 [66; 118]; OP, 90 [70; 120] as medians and 95% confidence intervals (CIs) of six rats for each group). Conversely, after 32 weeks of diet both OR and OP rats were partially responsive to 10 μg leptin i.c.v. as compared with CONT rats (24 h calorie intake as a percent of vehicle-treated rats: CONT rats, 60 [50; 67]; OR, 65 [50; 80]; OP, 80 [60; 98] as medians and 95% CIs of six rats for each group); the decrease of food intake following 200 μg leptin i.p. administration was similar in all the three groups (calorie intake as a percent of vehicle-treated rats: 86 [80; 92] as median and 95% CI). The long-term intake of HF diet caused hyperleptinemia, hyperinsulinemia and higher plasma glucose levels in OP rats as compared with CONT rats. Plasma thyroxine (T4) was lower in all the rats fed the HF diet as compared with CONT. i.c.v. administration of leptin after 32 weeks of diet restored normal insulin levels in OP rats. Moreover, leptin increased plasma T4 concentration and strongly enhanced GH mRNA expression in the pituitary of OP as well as OR rats (180±10% vs vehicle-treated rats). In conclusion, long-term intake of HF diet induced a partial central resistance to the anorectic effect of leptin in both lean and fat animals; the neuroendocrine effects of leptin on T4 and GH were preserved.
Thermal‐hydrodynamic modeling of bubbly flows with heat and mass transfer
Authors: Yeoh G. H. , Tu J. Y.
Published: December 2004

A three‐dimensional (3‐D) two‐fluid model coupled with the population balance equation is used to predict bubbly flows with the presence of heat and mass transfer processes, particularly on subcooled boiling flows at low pressures. To account for the nonuniform bubble distribution in the bulk liquid at subcooled conditions, the CFX MUSIG (MUltiple‐Size Group) model is further developed by incorporating the wall nucleation at the heated wall and condensation in the flow regime. Model predictions, covering a wide range of different mass and heat fluxes and inlet subcooling temperatures, are compared against local and axial measurements. For the local case, the bubble size predictions include the comparison of the empirical bubble diameter relationships adopted in the CFX boiling model. The study shows that good agreement is better achieved by the present model with respect to the radial distributions of the bubble Sauter diameter, void fraction, interfacial area concentration, and liquid velocity profiles. However, significant weakness prevails over the vapor velocity distribution. Work is in progress to circumvent the deficiency by considering additional momentum equations or developing an algebraic slip model to account for bubble separation. For the axial case, good agreement is also achieved for the axial distributions of the mean bubble Sauter diameter, void fraction, and interfacial area concentration profiles. Here, the model correctly represents the plateau at the initial boiling stages at upstream, typically found in low‐pressure subcooled boiling flows, followed by the significant increase of the void fraction at downstream. © 2004 American Institute of Chemical Engineers AIChE J, 51: 8–27, 2005
Automatic crosslingual thesaurus generated from the Hong Kong SAR Police Department Web corpus for crime analysis
Authors: Li Kar Wing , Yang Christopher C.
Published: December 2004

For the sake of national security, very large volumes of data and information are generated and gathered daily. Much of this data and information is written in different languages, stored in different locations, and may be seemingly unconnected. Crosslingual semantic interoperability is a major challenge to generate an overview of this disparate data and information so that it can be analyzed, shared, searched, and summarized. The recent terrorist attacks and the tragic events of September 11, 2001 have prompted increased attention on national security and criminal analysis. Many Asian countries and cities, such as Japan, Taiwan, and Singapore, have been advised that they may become the next targets of terrorist attacks. Semantic interoperability has been a focus in digital library research. Traditional information retrieval (IR) approaches normally require a document to share some common keywords with the query. Generating the associations for the related terms between the two term spaces of users and documents is an important issue. The problem can be viewed as the creation of a thesaurus. Apart from this, terrorists and criminals may communicate through letters, e‐mails, and faxes in languages other than English. The translation ambiguity significantly exacerbates the retrieval problem. The problem is expanded to crosslingual semantic interoperability. In this paper, we focus on the English/Chinese crosslingual semantic interoperability problem. However, the developed techniques are not limited to English and Chinese languages but can be applied to many other languages. English and Chinese are popular languages in the Asian region. Much information about national security or crime is communicated in these languages. An efficient automatically generated thesaurus between these languages is important to crosslingual information retrieval between English and Chinese languages. To facilitate crosslingual information retrieval, a corpus‐based approach uses the term co‐occurrence statistics in parallel or comparable corpora to construct a statistical translation model to cross the language boundary. In this paper, the text‐based approach to align English/Chinese Hong Kong Police press release documents from the Web is first presented. We also introduce an algorithmic approach to generate a robust knowledge base based on statistical correlation analysis of the semantics (knowledge) embedded in the bilingual press release corpus. The research output consisted of a thesaurus‐like, semantic network knowledge base, which can aid in semantics‐based crosslingual information management and retrieval.
User acceptance of Intelligence and Security Informatics technology: A study of COPLINK
Authors: Jen‐Hwa Hu Paul , Lin Chienting , Chen Hsinchun
Published: December 2004

The importance of Intelligence and Security Informatics (ISI) has significantly increased with the rapid and large‐scale migration of local/national security information from physical media to electronic platforms, including the Internet and information systems. Motivated by the significance of ISI in law enforcement (particularly in the digital government context) and the limited investigations of officers' technology‐acceptance decision‐making, we developed and empirically tested a factor model for explaining law‐enforcement officers' technology acceptance. Specifically, our empirical examination targeted the COPLINK technology and involved more than 280 police officers. Overall, our model shows a good fit to the data collected and exhibits satisfactory power for explaining law‐enforcement officers' technology acceptance decisions. Our findings have several implications for research and technology management practices in law enforcement, which are also discussed.
Zerstörungsfreie Untersuchungen an Fundamentplatten mit Ultraschallecho
Authors: Taffe Alexander , Niederleithinger Ernst , Krause Martin , Milmann Boris
Published: December 2004

Zerstörungsfreie Prüfverfahren im Bauwesen (ZfP‐Bau) dienen der Zustandsermittlung von Bauteilen und der Erkundung unzureichend dokumentierter Bausubstanz. Zur Untersuchung von Fundamentplatten wird das Ultraschallecho‐Verfahren vorgestellt. Es werden Anwendungshinweise zur Durchführung von Dickenmessungen, dem Lokalisieren von Pfählen und Streifenfundamenten unter einer Fundamentplatte gegeben. Anwendungsbeispiele für Untersuchungen an 30 cm, 75cm und 125 cm dicken Fundamentplatten mit verschiedenen Bewehrungsgehalten werden beschrieben. Darüber hinaus wird die bildgebende Darstellung der Ergebnisse, z. B. die Abbildung eingebauter Bewehrung, vorgestellt.
Study of the DNA/ethidium bromide interactions on mica surface by atomic force microscope: Influence of the surface friction
Authors: Pastré David , Piétrement Olivier , Zozime Alain , Le Cam Eric
Published: December 2004

The influence of mica surface on DNA/ethidium bromide interactions is investigated by atomic force microscopy (AFM). We describe the diffusion mechanism of a DNA molecule on a mica surface by using a simple analytical model. It appears that the DNA diffusion on a mica surface is limited by the surface friction due to the counterion correlations between the divalent counterions condensed on both mica and DNA surfaces. We also study the structural changes of linear DNA adsorbed on mica upon ethidium bromide binding by AFM. It turns out that linear DNA molecules adsorbed on a mica surface are unable to relieve the topological constraint upon ethidium bromide binding. In particular, strongly adsorbed molecules tend to be highly entangled, while loosely bound DNA molecules appear more extended with very few crossovers. Adsorbed DNA molecules cannot move freely on the surface because of the surface friction. Therefore, the topological constraint increases due to the ethidium bromide binding. Moreover, we show that ethidium bromide has a lower affinity for strongly bound molecules due to the topological constraint induced by the surface friction. © 2004 Wiley Periodicals, Inc. Biopolymers, 2005
A DFT‐Based Theoretical Investigation of the Mechanism of the PtCl2‐Mediated Cycloisomerization of Allenynes
Authors: Soriano Elena , Marco‐Contelles José
Published: December 2004

The mechanism of PtII‐catalyzed intramolecular cycloisomerization of allenyne systems has been extensively investigated by DFT calculations. Different mechanistic schemes have been proposed and discussed, including the Alder–ene reaction. The free energy results suggest that the kinetically preferred reaction pathway for precursors that are tri‐ and tetrasubstituted on the allene moiety should proceed by a five‐step mechanism. This would involve formation of a platina(IV)cyclopentene intermediate by selective engagement of the external π bond of the allene, which would undergo regioselective β‐H elimination from the equatorially disposed methyl group. A metal‐induced H migration leads to a second octahedral PtIV–chelate complex, which would yield the expected bicyclic system through an intramolecular migratory insertion step. Therefore, depending on the conformation of the initial η4‐reactant complex for trisubstituted patterns, two possible intermediates can be formed that would evolve through different paths. In these cases, the regio‐ and stereochemical outcomes predicted by the mechanistic scheme proposed agree with experimental data. Substituted precursors on the alkyne moiety follow a distinct, four‐step, mechanism also involving an oxidative cyclometalation process to an octahedral PtIV intermediate complex. Theoretical results reveal the kinetic preference for β‐H elimination from the allylic group rather than from the gem‐dimethyl group, which should account for the observed regioselectivity.
Decomposition of Neutral, Singly and Doubly Protonated Benzoquinone in the Gas Phase
Authors: Roithová Jana , Schröder Detlef , Schwarz Helmut
Published: December 2004

The unimolecular fragmentations of singly and doubly protonated ortho‐, meta‐, and para‐benzoquinones (BQH+ and BQH22+, respectively) are studied by tandem mass spectrometry. The dominant fragmentation pathways lead to the elimination of a neutral CO molecule from BQH+ and, by charge separation, to the expulsion of protonated CO from BQH22+. Reaction mechanisms are elucidated based on labeling experiments and UB3 LYP calculations. These results reveal that the respective reactions proceed in an analogous fashion to the decarbonylation of neutral benzoquinones, which decompose into carbon monoxide and cyclopentadienone. Single protonation facilitates all steps on the reaction pathway with neutral CO and O‐protonated cyclopentadienone as final products. In contrast, double protonation leads to an increase of the barriers for the decomposition yielding CO⋅H+ and O‐protonated cyclopentadienone. This major process of BQH22+ is accompanied by two minor channels, which lead to the elimination of neutral carbon monoxide and water, respectively. The proton affinity of the para‐BQH+ monocation is estimated as 3.6±0.3 eV.
Competition between Superexchange‐Mediated and Sequential Electron Transfer in a Bridged Donor–Acceptor System
Authors: Winters Mikael U. , Pettersson Karin , Mårtensson Jerker , Albinsson Bo
Published: December 2004

The temperature‐ and solvent‐dependence of photoinduced electron‐transfer reactions in a porphyrin‐based donor–bridge–acceptor (DBA) system is studied by fluorescence and transient absorption spectroscopy. Two competing processes occur: sequential and direct superexchange‐mediated electron transfer. In a weakly polar solvent (2‐methyltetrahydrofuran), only direct electron transfer from the excited donor to the appended acceptor is observed, and this process has weak temperature dependence. In polar solvents (butyronitrile and dimethylformamide), both processes are observed and the sequential electron transfer shows strong temperature dependence. In systems where both electron transfer processes are observed, the long‐range superexchange‐mediated process is more than two times faster than the sequential process, even though the donor–acceptor distance is significantly larger in the former case.
Mord, Brandstiftung, Sprengstoffanschläge: Analytische Chemie in der Kriminaltechnik
Authors: Schäfer Thomas
Published: December 2004

Auch Liebig trat schon als Sachverständiger im Rahmen eines Mordprozesses vor Gericht auf, um den Ausbruch eines merkwürdigen Brandes zu begutachten. Expertenwissen und moderne Analytik unterstützen auch heute die Arbeit von Polizei und Justiz. Je nach Spurenlage und Fragestellung wird ein breit gefächertes Methodenspektrum zum Einsatz gebracht.
Tödliches Ubiquitin‐Etikett
Authors: Jacoby Petra
Published: December 2004

Der diesjährige Chemie‐Nobelpreis wurde an Aaron Ciechanover und Avram Hershko vom Israel Institute of Technology in Haifa sowie an Irwin Rose von der University of California in Irvine vergeben. Ihre bahnbrechenden Entdeckungen darüber, wie Zellen unerwünschte Proteine selektiv zum Abbau markieren, lieferten die Basis für ein völlig neues Forschungsfeld.
Der Christmas‐Faktor
Authors: Roth Klaus
Published: December 2004

Verletzungen von Blutgefäßen sind für uns lebensbedrohend, und durch Verletzung entstandene Risse und Löcher müssen schnellstens abgedichtet werden. Durch die Blutstillung wird das Leck zunächst provisorisch verschlossen und durch die Blutgerinnung das Provisorium anschließend versteift, um die Wunde auch dauerhaft abzudichten. Dabei greifen über ein Dutzend als Gerinnungsfaktoren bezeichnete Proteine ein (Tabelle 1) und einer davon, der Faktor IX, wird nach dem kleinen Stephen Christmas benannt, denn durch ihn konnte dieser Faktor erstmals identifiziert werden. Entdecken wir die komplexe Chemie der Blutstillung und ‐gerinnung und wie uns ein kleiner Patient mit “seinem” Faktor bei deren Erforschung geholfen hat.
NiIIRuII and CuIIRuII Coordination Polymers Constructed from [Ru(CN)6]4−
Authors: Shek Iris Pui‐Yee , Yeung Wai‐Fun , Lau Tai‐Chu , Zhang Jing , Gao Song , Szeto Lap , Wong Wing‐Tak
Published: December 2004

The dimetallic compounds [Ni(2,3,2‐tet)]2[Ru(CN)6]·8H2O (1), [Ni(pn)2]2[Ru(CN)6]·5H2O (2) [Ni(tacd)(H2O)]2[Ru(CN)6]·8H2O (3) and {[Cu(dipn)]3[Ru(CN)6]}(ClO4)2·4H2O (4) [2,3,2‐tet = N,N′‐bis(2‐aminoethyl)‐1,3‐propanediamine, pn = 1,3‐diaminopropane, tacd = 1,5,9‐triazacyclododecane, dipn = dipropylenetriamine] have been prepared from the reaction of [Ru(CN)6]4− with [Ni(2,3,2‐tet)]2+, [Ni(pn)2]2+, [Ni(tacd)(H2O)]2+ and [Cu(dipn)]2+, respectively. Compounds 1 and 2 contain a two‐dimensional square network, compound 3 has a one‐dimensional, crossed‐double chain structure, while compound 4 has an unusual, two‐dimensional, double‐edged, honeycomb network. A very weak antiferromagnetic interaction is observed in 2. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
Preparation and Characterisation of CdII, HgII and PbII Complexes of a Macrodinucleating Hexaaza‐dithiophenolate Ligand
Authors: Lozan Vasile , Kersting Berthold
Published: December 2004

The ligating properties of a Robson‐type 24‐membered macrodinucleating hexaaza‐dithiophenolate ligand towards the heavy metal ions CdII, HgII and PbII have been examined. The complexation of H2LMe with CdCl2 or Cd(OAc)2 in the presence of triethylamine leads to monocationic [(LMe)Cd2(μ‐L′)]+ complexes bearing additional coligands [L′ = Cl− (2) or OAc− (3)]. With Hg(OAc)2 and Pb(OAc)2, the respective dicationic complexes [(LMe)Hg2]2+ (4) and [(LMe)Pb2]2+ (5) were obtained. The latter show no tendency to bind to further coligands. The crystal structure determinations of 2·BPh4 and 3·BPh4 revealed the presence of bowl‐shaped, calixarene‐like [(LMe)Cd2(μ‐L′)]+ cations featuring six‐coordinate CdII ions with N3S2Cl (2) or N3S2O (3) environments. The metal ions in the dications 4 and 5 display highly irregular N3S coordination environments, presumably as a consequence of the steric constraints imposed by the rigid macrocyclic nature of (LMe)2−. All complexes could also be fully characterised by 1H and 13C NMR spectroscopy. These results have thus established the ability of the macrodinucleating polyaza‐dithiophenolate ligand to support the formation of stable dinuclear complexes of toxic heavy metals. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)
A new conceptual hierarchy for identifying environmental sustainability metrics
Authors: Jin Xun , High Karen A.
Published: December 2004

Metric identification has received growing attention as more alternatives become available for quantifying the sustainability‐oriented performance of a target human activity. Failure to tackle the diversity in these alternatives has given rise to significant difficulties in comparing and interpreting the assessment results obtained from using various metrics. This paper explores some bottlenecks in identifying “appropriate” environmental sustainability metrics that specifically meet the needs of a sustainability assessor. A new conceptual hierarchy “stressor–status–effect–integrality–well‐being” (SSEIW) for metric classification is proposed. This hierarchy categorizes the full range of metrics into five levels, each of which measures the interested environmental outcomes in a different manner. This paper shows that the proposed hierarchy can be applied within the framework of life‐cycle assessment (LCA), which provides a promising solution to “best‐practice” metric identification as well as expanding the LCA applications to the sustainability field. © 2004 American Institute of Chemical Engineers Environ Prog, 2004
EGF‐stimulation activates the nuclear localization signal of SHP‐1
Authors: He Dandan , Song Xi , Liu Lijun , Burk David H. , Zhou G. Wayne
Published: December 2004

Protein tyrosine phosphatase SHP‐1 plays a critical role in the regulation of a variety of intracellular signaling pathways. SHP‐1 is predominantly expressed in the cells of hematopoietic origin, and is recognized as a negative regulator of lymphocyte development and activation. SHP‐1 consists of two Src homology 2 (SH2) domains and one protein tyrosine phosphatase (PTP) domain followed by a highly basic C‐terminal tail containing tyrosyl phosphorylation sites. It is unclear how the C‐terminal tail regulates SHP‐1 function. We report the examination of the subcellular localization of a variety of truncated or mutated SHP‐1 proteins fused with enhanced green fluorescent protein (EGFP) protein at either the N‐terminal or the C‐terminal end in different cell lines. Our data demonstrate that a nuclear localization signal (NLS) is located in the C‐terminal tail of SHP‐1 and the signal is primarily defined by three amino‐acid residues (KRK) at the C‐terminus. This signal is generally blocked in the native protein and can be exposed by fusing EGFP at the appropriate position or by domain truncation. We have also revealed that this NLS of SHP‐1 is triggered by epidermal growth factor (EGF) stimulation and mediates translocation of SHP‐1 from the cytosol to the nucleus in COS7 cell lines. These results not only demonstrate the importance of the C‐terminal tail of SHP‐1 in the regulation of nuclear localization, but also provide insights into its role in SHP‐1‐involved signal transduction pathways. J. Cell. Biochem. 94: 944–953, 2005. © 2004 Wiley‐Liss, Inc.