bluuebunny/crossref_metadata_2025 huggingface dataset:
Retinol has specific effects on binding of thyrotrophin to cultured porcine thyrocytes
Authors: Fröhlich Eleonore , Witke Anja , Czarnocka Barbara , Wahl Richard
Published: March 2005

Retinoids are potential candidates for the treatment of thyroid cancer. However, one of the disadvantages of these substances is their dedifferentiating effect on normal non-transformed thyrocytes. To identify conditions under which no dedifferentiating effect of retinol on normal thyrocytes can be observed, we determined iodide uptake, protein iodination, expression of sodium–iodide symporter (NIS) mRNA and protein, and the binding of iodine-125-labelled bTSH in cultured porcine thyrocytes. Combination of TSH and ≤6.5 μM retinol increased iodide uptake and protein iodination compared with TSH alone over the entire incubation time, whereas TSH plus ≥13 μM retinol increased the uptake of iodine-125 only during the first 12 h but decreased it after 30 h and longer. After ≥30 h incubation times with ≥13 μM retinol, the fraction of apoptotic cells was enhanced and proliferation decreased. The incubation with retinol enhanced the binding of [125I]bTSH to thyrocytes, but did not influence expression of the NIS. With low retinol concentrations, the effect on the binding of TSH apparently predominated and retinol increased thyroid function; with higher concentrations the pro-apoptotic effect of retinol overlapped and a two-phased time course resulted. It can be concluded that low concentrations of retinol also exert differentiating effects in normal thyrocytes.
Serum amyloid A3 expression is stimulated by dexamethasone and interleukin-6 in 3T3-L1 adipocytes
Authors: Fasshauer Mathias , Klein Johannes , Kralisch Susan , Klier Margit , Lossner Ulrike , Bluher Matthias , Paschke Ralf
Published: March 2005

A chronic increase in systemic levels of acute-phase reactants contributes to the development of insulin resistance and associated disorders such as cardiovascular disease. Recently, serum amyloid A3 (SAA3) has been characterized as an adipocyte-secreted acute-phase reactant, expression of which is dramatically increased in insulin resistance and obesity. To further clarify expression and regulation of this adipocytokine in fat, SAA3 mRNA was measured by quantitative real-time reverse transcriptase PCR during differentiation of 3T3-L1 adipocytes and after treatment with various hormones known to induce insulin resistance and contribute to atherosclerosis. SAA3 mRNA was dramatically induced up to 77-fold during differentiation of 3T3-L1 preadipocytes. Furthermore, 100 nM dexamethasone and 30 ng/ml interleukin (IL)-6 induced SAA3 mRNA by up to 11- and 4.8-fold, respectively, in a time-dependent fashion with significant stimulation observed at concentrations as low as 10 nM dexamethasone and 1 ng/ml IL-6. In contrast, insulin, isoproterenol and growth hormone did not influence SAA3 synthesis. Inhibitor studies suggested that the positive effect of IL-6 on SAA3 expression is at least in part mediated by Janus kinase 2. Taken together, our results show a differential regulation of SAA3 by glucocorticoids and IL-6 supporting an integrative role of this acute-phase reactant in the pathogenesis of insulin resistance and its link to obesity and cardiovascular disease.
Co-localization of nestin and insulin and expression of islet cell markers in long-term human pancreatic nestin-positive cell cultures
Authors: Maria-Engler Silvya Stuchi , Corrêa-Giannella Maria Lúcia C , Labriola Letícia , Krogh Karin , Colin Christian , Lojudice Fernando Henrique , Aita Carlos Alberto Mayora , de Oliveira Elizabeth Maria Costa , Corrêa Tatiana C Silveira , da Silva Irenice Cairo , Genzini Tercio , de Miranda Marcelo Perosa , Noronha Irene Lourdes , Vilela Luciano , Coimbra Cassio Negro , Mortara Renato A , Mares Guia Marcos , Eliaschewitz Freddy Goldberg , Sogayar Mari Cleide
Published: March 2005

Strategies to differentiate progenitor cells into β cells in vitro have been considered as an alternative to increase β cell availability prior to transplantation. It has recently been suggested that nestin-positive cells could be multipotential stem cells capable of expressing endocrine markers upon specific stimulation; however, this issue still remains controversial. Here, we characterized short- and long-term islet cell cultures derived from three different human islet preparations, with respect to expression of nestin and islet cell markers, using confocal microscopy and semi-quantitative RT-PCR. The number of nestin-positive cells was found to be strikingly high in long-term cultures. In addition, a large proportion (49.7%) of these nestin-positive cells, present in long-term culture, are shown to be proliferative, as judged by BrdU incorporation. The proportion of insulin-positive cells was found to be high in short-term (up to 28 days) cultures and declined thereafter, when cells were maintained in the presence of 10% serum, concomitantly with the decrease in insulin and PDX-1 expression. Interestingly, insulin and nestin co-expression was observed as a rare event in a small proportion of cells present in freshly isolated human islets as well as in purified islet cells cultured in vitro for long periods of time. In addition, upon long-term subculturing of nestin-positive cells in 10% serum, we observed reappearance of insulin expression at the mRNA level; when these cultures were shifted to 1% serum for a month, expression of insulin, glucagon and somatostatin was also detected, indicating that manipulating the culture conditions can be used to modulate the nestin-positive cell’s fate. Attempts to induce cell differentiation by plating nestin-positive cells onto Matrigel revealed that these cells tend to aggregate to form islet-like clusters, but this is not sufficient to increase insulin expression upon short-term culture. Our data corroborate previous findings indicating that, at least in vitro, nestin-positive cells may undergo the early stages of differentiation to an islet cell phenotype and that long-term cultures of nestin-positive human islet cells may be considered as a potential source of precursor cells to generate fully differentiated/ functional β cells.
Prolactin gene expression in mouse spleen helper T cells
Authors: Horiguchi K , Yagi S , Ono K , Nishiura Y , Tanaka M , Ishida M , Harigaya T
Published: March 2005

Prolactin (PRL) is a single-chain polypeptide hormone that is generally secreted from prolactin cells of the anterior pituitary gland into the blood circulation. However, recent studies indicate that the gene expression of prolactin is ectopic in several tissues across several species. These studies found that lymphocytes also produce PRL, which is involved in the immunoregulatory system. Here, we searched for PRL messenger ribonucleic acid (mRNA), using the reverse transcriptase-polymerase chain reaction (RT-PCR) and Southern blotting in the spleens of mice at various growth stages. We also localized mouse prolactin (mPRL) and its mRNA in the spleens of 30- and 60-day-old mice by immunohistochemistry and in situ hybridization respectively. The mPRL gene was expressed in all spleen samples at 0–60 days postpartum. We localized mPRL mRNA in the sheathed artery, periarterial lymphatic sheath and the marginal zone of the spleen. Moreover, we detected mPRL in essentially the same area as its mRNA. Furthermore, we performed double-fluorescence immunohistochemical staining for mPRL and mouse CD4 that is specifically produced in helper T cells, or for mPRL and mouse CD19 or CD40 specified B cells. We colocalized mPRL immunoreactivity only in some CD4-immunopositive cells. These results clearly suggest that T cells synthesize mPRL in the mouse spleen.
Thrombopoietin regulates proliferation, apoptosis, secretory activity and intracellular messengers in porcine ovarian follicular cells: involvement of protein kinase A
Authors: Sirotkin A V , Sanislo P , Schaeffer H-J , Florkovičová I , Kotwica J , Bulla J , Hetényi L
Published: March 2005

Thrombopoietin (TPO) is known to be involved in megakariocytopoesis, but its role in the control of ovarian function is unknown. The aims of this study were to determine whether TPO can regulate the proliferation, apoptosis and secretory activity of ovarian cells, to identify possible intracellular mediators of TPO action, especially protein kinase A (PKA), and to define their interrelationships within ovarian cells. We investigated the effect of TPO treatment (0, 1, 10 or 100 ng/ml) on the following characteristics of cultured porcine ovarian follicles, determined using SDS-PAGE and Western blotting, immunocytochemistry, RIA and ELISA: the expression of intracellular peptides associated with proliferation (PCNA), apoptosis (Bax), tyrosine kinase (TK, phosphotyrosine), Cdc2/p34 kinase, PKA and the transcription factor CREB-1, and the secretion of progesterone, androstenedione, estradiol-17β, oxytocin, inhibin A, inhibin B, IGF-I, transforming growth factor-2β (TGF-2β) and IGF-binding protein 3 (IGFBP-3). The involvement of PKA-dependent pathways was examined by evaluating the effect of a PKA blocker (KT5720, 1 μg/ml), either alone or in combination with TPO, on the parameters listed above.

A TPO-induced increase in expression of PCNA, Bax, PKA, TK, Cdc2/p34 and CREB was observed. Furthermore, TPO was able to inhibit androstenedione, estradiol, TGF-2β and IGFBP-3 secretion, and to stimulate oxytocin, inhibin A, inhibin B and IGF-I secretion. Progesterone secretion was not stimulated. The PKA blocker KT5720, when given alone, reduced the expression of Bax and TGF-2β, augmented the expression of PKA, CREB and oxytocin, but did not influence the secretion of progesterone, androstenedione, estradiol, IGFBP-3, inhibins A and B or IGF-I. When given together with TPO, the PKA blocker prevented or reversed the action of TPO on PKA, CREB, androstenedione, estradiol, IGFBP-3, oxytocin, but not its effect on Bax, TGF-2β or inhibin B. On the other hand, treatment with KT5720 augmented the effect of TPO on progesterone, inhibin A and IGF-I.

These results provide the first evidence that TPO may be a potent regulator of ovarian function (e.g. proliferation, apoptosis and the secretion of peptide hormones, steroids, growth factors and growth factor-binding protein, as well as of the expression of some intracellular messengers). Furthermore, they demonstrated the importance of PKA in controlling these functions and in mediating the effects of TPO on ovarian cells. It remains possible that other (TK- and Cdc2/p34-dependent) intracellular mechanisms are also involved in mediating TPO action on the ovary.
Effects of overexpression of CXCL10 (cytokine-responsive gene-2) on MA-10 mouse Leydig tumor cell steroidogenesis and proliferation
Authors: Nagpal Madan L , Chen Yue , Lin Tu
Published: March 2005

Chemokines have been implicated in tumor growth, angiogenesis, metastasis and the host immune response to malignant cells. Infection and autoimmune disorders can reduce androgen production by Leydig cells and adversely affect spermatogenesis. Cytokine-responsive gene-2 (crg-2) (systematic name CXCL10, also known as interferon-γ-inducible protein 10 (IP-10)) is a potent chemokine expressed predominantly by macrophages and Leydig cells in the testis. CXCL10 binds to CXCR3 receptor (a G-protein-coupled receptor) and acts via Giα protein. We have shown previously that CXCL10 is differentially expressed in normal Leydig cells, inhibited by human chorionic gonadotropin and induced by interferon-γ, interleukin-1α and tumor necrosis factor-α. The purpose of the present study was to determine the effects of overexpression of CXCL10 by transfection experiments in MA-10 cells on cell growth, CXCR3 expression, progesterone synthesis and steroidogenic acute regulatory protein (StAR D1, a key regulatory factor in steroidogenesis) gene expression. We cloned the complete CXCL10 cDNA in a mammalian expression vector with the CMV promoter, pcDNA3.1D/V5-His-TOPO, and confirmed its expression with rat CXCL10 antibody and V5 antibody. Results showed large amounts of CXCL10 protein secreted in the medium in the CXCL10 transfectants by Western blotting. The production of CXCL10 mRNA ranged from 30–50-fold more (n=6) in the transfected cells than the control cells, as determined by semiquantitative and real-time RT-PCR. 8-Br-cAMP downregulated CXCL10 mRNA expression and stimulated CXCR3 mRNA expression. Transfection of MA-10 cells with CXCL10 decreased cAMP-induced progesterone synthesis from 38.5±1.7 ng/ml (1.5×105 cells/ml) in control cells to 23.2±1.5 ng in transfected cells (P<0.01). 8-Br-cAMP (0.2 mM)-induced StAR D1 mRNA was decreased 30–40% by transfection with CXCL10. Interestingly, overexpression of CXCL10 induced the expression of its receptor CXCR3 gene, as determined by RT-PCR and fluorescence-activated cell sorter (FACS) analysis. Transfection of CXCL10 also significantly decreased insulin-like growth factor-I (IGF-I, 100 ng/ ml)-induced [3H]thymidine incorporation into DNA. These data suggest that CXCL10 also inhibits MA-10 tumor cell proliferation. In conclusion, CXCL10 inhibits StAR D1 expression, decreases progesterone synthesis and inhibits cell proliferation. CXCL10 has the potential to be used in gene therapy for prostate cancer due to its antiangiogenic effect and its inhibitory effect on steroidogenesis.
Effects of glucocorticoids on Fas gene expression in bovine blood neutrophils
Authors: Chang Ling-Chu , Madsen Sally A , Toelboell Trine , Weber Patty S D , Burton Jeanne L
Published: March 2005

Blood neutrophils are extremely short-lived cells that are programmed for rapid apoptosis after differentiation in bone marrow. Recently, glucocorticoids have been shown to prolong survival of human and rodent neutrophils, but the mechanisms and implications for leukocyte homeostasis and health are unclear. In this study, we investigated the effects of endogenous and exogenous glucocorticoids on Fas expression in bovine neutrophils because Fas is a major death receptor that stimulates apoptosis in circulating cells. Our study subjects were four periparturient dairy cows whose blood concentrations of cortisol peaked at calving, 15 dexamethasone-treated steers and three untreated steers whose neutrophils were exposed to dexamethasone in vitro. Fas mRNA abundance changes in collected neutrophils were monitored numerous times relative to the in vivo glucocorticoid challenges, and the relationships between these data and circulating neutrophil counts were estimated by correlation analyses. Fas mRNA and protein abundance, caspase 8 activity, and survival of neutrophils in vitro were also monitored in the presence and absence of dexamethasone. In the periparturient cows, Fas mRNA abundance in circulating neutrophils showed a sharp decrease between calving and 12 h postpartum. Based on PROC CORR analysis (SAS), this correlated negatively with blood neutrophil count (r=−0.634; P=0.0009) and serum cortisol concentration (r=−0.659; P<0.0001), but showed no relationship with serum progesterone or estradiol concentrations (P ≥0.09). Administration of dexamethasone to steers also caused a pronounced reduction in neutrophil Fas mRNA abundance that persisted for 12 h and correlated negatively with blood neutrophil count (r=–0.748; P=0.0021). In vitro, dexamethasone caused dose-dependent loss of GR proteins from the cytosol of neutrophils concurrently with Fas mRNA downregulation, which was inhibited by the glucocorticoid receptor (GR) antagonist, RU486. Dexamethasone treatment of cultured neutrophils also reduced surface Fas expression, spontaneous and sFasL-induced caspase 8 activity, and rate of apoptosis in the cells. Taken together, these in vivo and in vitro results suggest that glucocorticoids inhibit Fas expression in bovine blood neutrophils via GR activation, possibly contributing to the cells’ increased longevity in culture and the pronounced neutrophilia observed in parturient cows and hormone-treated steers. We thus conclude that glucocorticoid-activated GR may change the homeostasis of circulating neutrophils, in part through its negative effects on Fas gene expression and downstream apoptosis signaling pathways.
Regulation of human villous trophoblast by insulin-like growth factors and insulin-like growth factor-binding protein-1
Authors: Hills F A , Elder M G , Chard T , Sullivan M H F
Published: March 2005

Many studies have implicated the insulin-like growth factors (IGFs) and insulin-like growth factor-binding protein-1 (IGFBP-1) in the control of the feto–maternal interface of human pregnancy, but many of the data are from cell lines derived from primary trophoblast or from extravillous trophoblast. We have obtained highly enriched villous cytotrophoblast (VCT) from first trimester and term human placentae, and investigated the effects of IGF-I, IGF-II and phosphoisoforms of IGFBP-1. First trimester villous trophoblast cells were regulated by all these factors. IGF-II increased cell numbers 3.5-fold after 96 h in culture, and IGF-I had less effect (1.5-fold increase) (both P<0.05). IGF-II also had a greater effect on the levels of matrix metalloproteinase (MMP)-2 and MMP-9. Phosphorylated and non-phosphorylated iso-forms of IGFBP-1 added alone increased cell numbers and MMP levels (P<0.05). IGFBP-1 did not modify the effects of IGF-II on cell numbers or on MMP production. Term VCT numbers and MMP production in vitro were unaffected by IGFs (P>0.05). Cell numbers were increased only by 100 nM IGFBP-1 isoforms (P<0.05), whereas MMP levels released from term cells were optimally increased by 1–10 nM IGFBP-1. Overall, our data show that IGFs regulate only first trimester, but not term, VCT. IGFBP-1 regulates VCT from both gestations, but the effects are concentration and end-point specific. In particular, first trimester cell numbers are more affected by low levels of IGFBP-1, whereas high levels of IGFBP-1 are needed to increase MMP and the converse applies to term VCT; low levels of IGFBP-1 have more effect on MMP levels.
Reactive oxygen species blockade and action of insulin on expression of angiotensinogen gene in proximal tubular cells
Authors: Hsieh Tusty-Jiuan , Fustier Pierre , Wei Chih-Chang , Zhang Shao-Ling , Filep Janos G , Tang Shiow-Shiu , Ingelfinger Julie R , Fantus I George , Hamet Pavel , Chan John S D
Published: March 2005

We reported previously that insulin inhibits the stimulatory effect of high glucose on the expression of angiotensinogen (ANG) gene in both rat immortalized renal proximal tubular cells (IRPTCs) and non-diabetic rat renal proximal tubular cells (RPTCs), but has no effect in diabetic rat RPTCs. In the present study we investigated whether hyperglycaemia-induced resistance to the insulin-induced inhibition of expression of the ANG gene is mediated via the generation of reactive oxygen species (ROS) in RPTCs. Rat IRPTCs were cultured for 2 weeks in high-glucose (25 mM) or normal-glucose (5 mM) medium plus angiotensin II (Ang II) with or without a superoxide scavenger (tiron), or inhibitors of: NADPH oxidase (diphenylene iodinium, DPI), Ang II type 1 and 2 receptors (losartan and PD123319), angiotensin-converting enzyme (perindopril), protein kinase C (GF 109203X), or glutamine:fructose-6-phosphate amino-transferase (azaserine). Cellular generation of ROS, and ANG and renin mRNA levels were assessed by lucigenin assay and specific reverse transcriptase-PCR respectively. Phosphorylation of p44/42 mitogen-activated protein kinase (p44/42 MAPK) was evaluated by western blotting. Prolonged exposure of IRPTCs to high concentrations of glucose or Ang II evoked generation of ROS and resistance to the insulin-induced inhibition of expression of the ANG gene and of p44/42 MAPK phosphorylation. Co-incubation of IRPTCs with tiron, DPI, losartan, PD123319, perindopril, GF 109203X or azaserine prevented ROS generation, restoring the inhibitory action of insulin on ANG gene expression and on p44/42 MAPK phosphorylation. In conclusion, our studies demonstrate that blockade of both ROS generation and activation of the intrarenal renin–angiotensin system improves the inhibitory action of insulin on ANG gene expression in IRPTCs in conditions of high glucose.
Insulin-like growth factor-I signaling is modified during chondrocyte differentiation
Authors: Phornphutkul Chanika , Wu Ke-Ying , Yang Xu , Chen Qian , Gruppuso Philip A
Published: March 2005

Insulin-like growth factor-I (IGF-I) is a critical regulator of skeletal growth. While IGF-I has been shown to be a potent chondrocyte mitogen in vitro, its role in chondrocyte differentiation is less well characterized. We chose to study the action of IGF-I on an accepted model of chondrocyte differentiation, the ATDC5 cell line. Insulin concentrations sufficiently high to interact with the IGF-I receptor are routinely used to induce ATDC5 cells to differentiate. Therefore, we first examined the ability of IGF-I to promote chondrocyte differentiation at physiological concentrations. IGF-I could induce differentiation of these cells at concentrations below 10 nM. However, increasing IGF-I concentrations were less potent at inducing differentiation. We hypothesized that mitogenic effects of IGF-I might inhibit its differentiating effects. Indeed, the extracellular-signal-regulated kinase (ERK)-pathway inhibitor PD98059 inhibited ATDC5 cell DNA synthesis while enhancing differentiation. This suggested that the ability of IGF-I to promote both proliferation and differentiation might require that its signaling be modulated through the differentiation process. We therefore compared IGF-I-mediated ERK activation in proliferating and hypertrophic chondrocytes. IGF-I potently induced ERK activation in proliferating cells, but minimal ERK response was seen in hypertrophic cells. In contrast, IGF-I-mediated Akt activation was unchanged by differentiation, indicating intact upstream IGF-I receptor signaling. Similar findings were observed in the RCJ3.1C5.18 chondrogenic cell line and in primary chick chondrocytes. We conclude that IGF-I promotes both proliferation and differentiation of chondrocytes and that the differentiation effects of IGF-I may require uncoupling of signaling to the ERK pathway.
Cloning and functional expression of the equine luteinizing hormone/chorionic gonadotrophin receptor
Authors: Saint-Dizier Marie , Foulon-Gauze Florence , Lecompte François , Combarnous Yves , Chopineau Maryse
Published: March 2005

Pituitary equine luteinizing hormone (eLH) and fetal chorionic gonadotrophin (eCG) have identical polypeptidic chains, but different linked carbohydrates. In equine tissues, eCG and eLH bind only to the LH/CG receptor (eLH/CG-R) and have no FSH activity. However, radio-receptor assays on equine luteal or testicular tissues have shown that eCG binds to the eLH/CG-R with only 2–4% of the binding activity of eLH. In order to study the structure–function relationship of eLH and eCG in a homologous sytem, we undertook the cloning and functional expression of the eLH/CG-R.

Based on sequence homologies among mammalian sequences for the LH/CG-R, overlapping partial fragments of LH/CG-R cDNAs were obtained from mare luteal RNA using reverse transcription-PCR and 5′-rapid amplification of cDNA ends. Ligations of the partial cDNA fragments encoded a part of the signal peptide followed by a putative 672 amino acid eLH/CG-R mature protein. The mature eLH/CG-R displayed 88.2–92.8% overall sequence homology with the other mammalian LH/CG-Rs and contained one unique seventh N-glycosylation site in its extracellular domain.

COS-7 cells were transiently transfected with a cDNA construct encoding an engineered complete signal peptide and the mature eLH/CG-R. Membrane preparations from transfected COS-7 cells bound 125I-eLH with high affinity (Kd 3.8 × 10−10 M). On a molar basis, eCG competed with 125I-eLH on membrane preparations with only 12.4% of the eLH binding activity. In transfected COS-7, both eLH and eCG increased the extracellular cAMP concentration in a dose-dependent manner, whereas eFSH did not. Furthermore, on a molar basis, eCG stimulated cAMP production with only 13.9% of the eLH stimulating activity.

We conclude that the cloned cDNA encodes a The differences functional eLH/CG-R. between eLH and eCG activities towards this receptor will be useful in studies of the influence of carbohydrates on gonadotrophin receptor binding and activation.
Characteristics of 3,5,3′-triiodothyronine (T3)-uptake system of tadpole red blood cells: effect of endocrine-disrupting chemicals on cellular T3 response
Authors: Shimada N , Yamauchi K
Published: March 2005

We characterized the 3,5,3′-L-triiodothyronine (T3)- uptake system on the plasma membrane of Rana catesbeiana tadpole red blood cells (RBCs) in the presence of a variety of inhibitors and potentially competing amino acids. Saturable [125I]T3 uptake was inhibited by phloretin, monodansylcadaverine, bromosulfophthalein, sodium taurocholate and tryptophan. Saturable uptake obeyed simple Michaelis–Menten kinetics with an apparent Km of 110 nM and a Vmax of 2.5 pmol/min per 106 cells at 23 °C. These results suggested that a large proportion of T3 transported into RBCs was mediated by the aromatic amino acid transporter (System T)-linked transporter. To investigate the effect of endocrine-disrupting chemicals (EDCs) on [125I]T3 uptake, RBCs were incubated with [125I]T3 in the presence of each chemical. Among the test chemicals, di-n-butyl phthalate, n-butylbenzyl phthalate and the miticide, dicofol, were the most powerful inhibitors of [125I]T3 uptake, with an IC50 of 2.2 μM, which was one order of magnitude greater than that for T3 (IC50, 0.14 μM), and diethylstilbestrol and ethinylestradiol were modest inhibitors. Tributyltin accelerated saturable initial [125I]T3 uptake by 2-fold at 3.2 μM. When RBCs were cultured with 10 nM T3 at 25 °C for 2 days in the presence of monodansylcadaverine, ethinylestradiol, ioxynil or dicofol at the defined concentrations, these compounds inhibited significantly the induction of the thyroid hormone receptor α gene by T3. However, not all chemicals competed with T3 binding to the receptor at the same concentrations. Our results raise the possibility that the T3-uptake system on the plasma membrane of the tadpole RBCs could be a candidate target site for some EDCs and can modulate cellular T3 response.
Postprandial changes in plasma GH and insulin concentrations, and responses to stimulation with GH-releasing hormone (GHRH) and GHRP-6 in calves around weaning
Authors: Katoh K , Furukawa G , Kitade K , Katsumata N , Kobayashi Y , Obara Y
Published: March 2005

Changes in plasma concentrations of GH and insulin in response to feeding and stimulation with GH-releasing hormone (GHRH) or GH-releasing peptide (GHRP-6, a ligand for endogenous GH secretagogue receptors) were compared between 3-week-old (milk-fed) and 12-week-old (concentrate and hay-fed) calves. Feeding of a milk-replacer diet in 3-week-old animals significantly increased the basal (prefeeding) concentrations of GH, insulin and glucose in plasma, whereas feeding of concentrate and hay in 12-week-old animals did not cause a significant change in these traits. However, in the animals maintained on a milk-replacer diet until 12 weeks of age, postprandial plasma GH concentrations and AUC (area under the curve) were not different from those in the age-matched weaned group. The venous injection of either GHRH (0.25 μg/kg) or GHRP-6 (2.5 μg/kg) significantly increased plasma GH concentrations in both 3- and 12-week-old animals, but GH AUC was significantly greater in 3-week-old than in 12-week-old animals. Insulin concentration was transiently but significantly increased by the injection of GHRP-6 only in 12-week-old animals, the AUC being greater in 12-week-old than 3-week-old animals. From these results, we conclude that postprandial levels of plasma GH and insulin concentrations are altered after weaning and by aging, and that the quality of diets or development of the neuroendocrine functions in the digestive–pituitary system may be involved in this alteration.
Reduced LH sensitivity in vivo and in vitro of corpora lutea induced during anoestrus by GnRH, and during the late breeding season, in Scottish Blackface ewes
Authors: Bramley T A , Stirling D , Menzies G S , Baird D T
Published: March 2005

Scottish Blackface ewes were synchronised in mid-breeding (November; group 1; n=12 ewes) or late-breeding season (March; group 2; n=16). Anoestrous ewes (May) were treated with progestagen sponges for 7 days and then given 250 ng GnRH 3-hourly for 24 h, 2-hourly for 24 h and hourly for a further 24 h (group 3; n=12). A second group of anoestrous ewes (group 4, n=19) received three bolus injections (30 μg) of GnRH at 90-min intervals without progestagen pretreatment. After ovulation, ewes were bled twice daily until slaughter (day 4 or day 12: oestrus=day 0). Mid-breeding season (group 1) and anoestrous ewes in group 3 formed ‘adequate’ corpora lutea (CL) with high plasma progesterone levels (3–4 ng/ml) maintained for at least 12 days, and responded in vivo to ovine LH (oLH) (10 μg) with a rise in plasma progesterone on day 11 (group 3, but not group 1, ewes also responded on day 3). CL minces from these ewes responded to human chorionic gonadotrophin (hCG) in vitro with a dose-dependent increase in progesterone secretion. Ewes in group 4 had a foreshortened luteal phase (8–10 days) and low plasma progesterone levels (~1 ng/ml), consistent with formation of inadequate CL. LH injection failed to induce a significant plasma progesterone increase. Furthermore, although progesterone secretion in vitro in response to maximally stimulating doses of hCG or dibutyryl cAMP (dbcAMP) was similar to that in adequate CL, the sensitivity of these CL to hCG (EC (effective concentration)50, 1 IU hCG/ml) was reduced 10-fold compared with adequate CL (EC50, 0.1 IU hCG/ml; P<0.01). Ewes that ovulated in the late breeding season (group 2) had high plasma progesterone, although levels began to decrease after day 10. Injection of oLH in vivo increased plasma progesterone. However, sensitivity to hCG in vitro (EC50, 0.5 IU hCG/ml) was intermediate between that of adequate luteal tissue (groups 1 and 3; EC50, 0.1 IU/ml) and that of group 4 ewes (EC50, 1 IU hCG/ml). Our data demonstrate a markedly reduced luteal sensitivity to LH in vivo and hCG in vitro in Scottish Blackface ewes with inadequate CL, and suggest that a similar loss of sensitivity to LH may occur in the late breeding season.
Stem cell therapy for diabetes: do we need to make beta cells?
Authors: Burns Christopher J , Persaud Shanta J , Jones Peter M
Published: March 2005

Type 1 diabetes can now be ameliorated by islet transplantation, although this treatment is restricted by the insufficient supply of islet tissue. The need for an essentially limitless supply of a substitute for primary human islets of Langerhans has led to research into the suitability of stem/progenitor cells to generate insulin-producing cells to use in replacement therapies for diabetes. Although there has been much research in this area, an efficient and reproducible protocol for the differentiation of stem cells into functional insulin-secreting β-cells that are suitable for transplantation has yet to be reported. In this commentary we examine the minimum requirements for replacement β-cells and outline some of the potential sources of these cells. We also argue that the generation of the ‘perfect’ beta-cell may not necessarily lead to the most suitable tissue for transplantation.
Serum MEPE-ASARM-peptides are elevated in X-linked rickets (HYP): implications for phosphaturia and rickets
Authors: Bresler Doron , Bruder Jan , Mohnike Klaus , Fraser William D , Rowe Peter S N
Published: March 2005

MEPE (Matrix Extracellular PhosphoglycoprotEin) expression is markedly elevated in X-linked-hypophosphatemic-rickets (HYP) and tumor-induced osteomalacia (TIO). In normal individuals, circulating serum-levels of MEPE are tightly correlated with serum-phosphorus, parathyroid hormone (PTH) and bone mineral density (BMD). Also, MEPE derived, C-terminal ASARM-peptides are candidate minhibins and/or phosphatonins. Our aims were to determine: 1. whether MEPE-ASARM-peptide(s) are abnormally elevated in HYP/hyp serum, and, 2. whether the ASARM-peptide(s) accumulate in hyp mice kidney renal-tubules. Using a specific competitive ELISA we measured a five fold increase (P=0.007) of serum ASARM-peptide(s) in human HYP patients (normal subjects 3.25 μM n=9; s.e.m.=0.51 and HYP-patients 15.74 μM, n=9; s.e.m.=3.32). A 6.23 fold increase (P=0.008) was measured in hyp male mice compared with their normal male siblings (normal-siblings, 3.73 μM, s.e.m.=0.57, n=3; and hyp-mice 23.4 μM, n=3, s.e.m.=4.01). Renal immuno-histological screening also revealed a dramatic increase of ASARM-peptides in regions anatomically consistent with the proximal convoluted tubules. This study demonstrates for the first time that markedly elevated serum levels of protease-resistant ASARM-peptide(s) occur in HYP/hyp and they accumulate in murine hyp kidneys. These peptides are thus likely responsible for the phosphaturia and defective mineralization in HYP/hyp and TIO.
Coronally Repositioning the Cemento‐Enamel Junction to Address Gingival Margin Discrepancies
Authors: McNeely Thomas E.
Published: March 2005

Background: Gingival margin discrepancies, especially in the esthetic zone, can pose a challenge for the restorative dentist. Surgical clinical crown lengthening and orthodontic tooth movement are most often used to treat these situations. In this report, an additional surgical technique will be discussed with its indications for use.

Methods: Three cases are presented, each with a different type of gingival margin discrepancy. The surgical technique used was the same for all cases. It involved establishing a new, more coronally positioned cementoenamel junction (CEJ) through the use of a finishing bur and curets. The newly exposed root surface was then covered with connective tissue, thus effecting a movement of the gingival margin in a coronal position.

Results: Clinical outcomes resulted in a more natural soft tissue relationship between the treated tooth and the adjacent dentition. The three cases presented did not appear to have any negative periodontal or restorative consequences following the procedure.

Conclusions: This report presents another technique which can be considered when the clinician is faced with the need to move the gingival margin in a coronal direction. Within the guidelines presented, this technique appears to be predictable, less complicated, and less time consuming to carry out when compared with other available options. J Periodontol 2005;76:138‐142.
Langerhans‐Cell Histiocytosis: A Clinical Case Without Bone Involvement
Authors: Manfredi M. , Corradi D. , Vescovi P.
Published: March 2005

Background: Langerhans‐cell histiocytosis (LCH) is a group of rare disorders histologically characterized by the proliferation of Langerhans cells. Multiple organs and systems may be involved by the disease. Typically, there is bone involvement and, less frequently, lesions may be found in the lungs, liver, lymph nodes, skin, and mucosae. Oral soft tissue lesions without bone involvement are rare.

Methods: We report a case of a 23‐year‐old man with LCH detected by oral soft tissue, cutaneous, and lung lesions.

Results: Due to the oral lesion diagnosis, important procedures were performed, which determined the staging of the disease.

Conclusion: Gingival lesions could be one of the first manifestations of LCH. The periodontist should recognize and detect this important pathology with oral involvement. J Periodontol 2005;76:143‐147.
Non‐Surgical Periodontal Therapy With Adjunctive Topical Doxycycline: A Double‐Masked, Randomized, Controlled Multicenter Study. II. Microbiological Results
Authors: Ratka‐Krüger Petra , Schacher Beate , Bürklin Thomas , Böddinghaus Boris , Holle Rolf , Renggli Heinz H. , Eickholz Peter , Kim Ti‐Sun
Published: March 2005

Background: Topical application of active substances offers an additional option in periodontal therapy. The aim of this study was to examine the influence of the administration of a novel, biodegradable 14% doxycycline gel on microbiological findings, in connection with scaling and root planing.

Methods: One hundred ten patients in three centers (Frankfurt and Heidelberg, Germany; Nijmegen, The Netherlands) with moderate to advanced periodontitis were evaluated in this randomized, double‐masked, split‐mouth clinical trial. In each patient, three test teeth were randomly assigned to one of three treatment modalities: 1) scaling and root planing (SRP) alone; 2) SRP with subgingival placebo gel (VEH); or 3) SRP and 14% doxycycline gel (DOX). Subgingival plaque samples were analyzed at baseline and 3 and 6 months after therapy for Actinobacillus actinomycetemcomitans (A.a.), Tannerella forsythensis (T.f.), Porphyromonas gingivalis (P.g.), and Treponema denticola (T.d.) using a RNA probe. Samples from 10 patients were tested for resistance against doxycycline, amoxicillin/clavulanic acid, cefoxitin, clindamycin, and metronidazole using agar diffusion testing.

Results: The largest decrease in pathogens was found after 3 months, with the most pronounced differences between DOX and SRP (P <0.05). At 6 months, pathogens were still reduced markedly in all groups. Treatment results were consolidated for VEH and DOX, with a slight deterioration for SRP (DOX versus SRP: P <0.001). Resistance was observed to amoxycillin/clavulanic acid, cefoxitin, clindamycin, and metronidazole (four isolates) but not to doxycycline.

Conclusion: The addition of subgingival instillation of a 14% doxycycline gel resulted in pronounced reduction of periodontal pathogens after 3 months and stabilizing results up to 6 months after therapy. Resistance to doxycycline was not induced. J Periodontol 2005;76:66‐74.
Taxonomic affinities and evolutionary history of the early Pleistocene hominids of Java: Dentognathic evidence
Authors: Kaifu Yousuke , Baba Hisao , Aziz Fachroel , Indriati Etty , Schrenk Friedemann , Jacob Teuku
Published: March 2005

Temporal changes, within‐group variation, and phylogenetic positions of the Early Pleistocene Javanese hominids remain unclear. Recent debate focused on the age of the oldest Javanese hominids, but the argument so far includes little morphological basis for the fossils. To approach these questions, we analyzed a comprehensive dentognathic sample from Sangiran, which includes most of the existing hominid mandibles and teeth from the Early Pleistocene of Java. The sample was divided into chronologically younger and older groups. We examined morphological differences between these chronological groups, and investigated their affinities with other hominid groups from Africa and Eurasia. The results indicated that 1) there are remarkable morphological differences between the chronologically younger and older groups of Java, 2) the chronologically younger group is morphologically advanced, showing a similar degree of dentognathic reduction to that of Middle Pleistocene Chinese H. erectus, and 3) the chronologically older group exhibits some features that are equally primitive as or more primitive than early H. erectus of Africa. These findings suggest that the evolutionary history of early Javanese H. erectus was more dynamic than previously thought. Coupled with recent discoveries of the earliest form of H. erectus from Dmanisi, Georgia, the primitive aspects of the oldest Javanese hominid remains suggest that hominid groups prior to the grade of ca. 1.8–1.5 Ma African early H. erectus dispersed into eastern Eurasia during the earlier Early Pleistocene, although the age of the Javanese hominids themselves is yet to be resolved. Subsequent periods of the Early Pleistocene witnessed remarkable changes in the Javanese hominid record, which are ascribed either to significant in situ evolution or replacement of populations. Am J Phys Anthropol, 2005. © 2005 Wiley‐Liss, Inc.
Lack of trastuzumab activity in nonsmall cell lung carcinoma with overexpression of erb‐B2
Authors: Clamon Gerald , Herndon James , Kern Jeffrey , Govindan Ramaswamy , Garst Jennifer , Watson Dorothy , Green Mark
Published: March 2005

BACKGROUND

The overexpression of HER‐2 occurs in a minority of patients with nonsmall cell lung carcinoma. Trastuzumab, which is a monoclonal antibody to HER‐2, is an effective treatment in some women with breast carcinomas that overexpress HER‐2, as demonstrated by immunohistochemistry. The objective of this Phase II study was to determine whether trastuzumab would effect responses in patients with nonsmall cell lung carcinoma who had tumors that overexpressed HER‐2.

METHODS

Patients were required to have Stage IIIB or Stage IV nonsmall cell lung carcinoma and tumors with 2+ or 3+ expression of HER‐2, as determined with immunohistochemistry, and they may have received up to 1 prior chemotherapy regimen. Trastuzumab at a dose of 4 mg/kg was given intravenously on Week 1; then, weekly doses of 2 mg/kg were given. Response revaluation was performed every 8 weeks.

RESULTS

Among 209 screened patients, 24 patients (11%) had tumors with 2+ or 3+ expression of HER‐2. One patient achieved a partial response, and one patient experienced a treatment‐related death due to pulmonary toxicity.

CONCLUSIONS

Single‐agent trastuzumab did not exhibit significant clinical activity against nonsmall cell lung carcinoma when HER‐2 expression levels were measured by immunohistochemistry. Cancer 2005. © 2005 American Cancer Society.
Distances in random graphs with finite variance degrees
Authors: van der Hofstad Remco , Hooghiemstra Gerard , Van Mieghem Piet
Published: March 2005

In this paper we study a random graph withNnodes, where nodejhas degreeDjand {Dj}are i.i.d. with ℙ(Dj≤x) =F(x). We assume that 1 −F(x) ≤cx−τ+1for some τ > 3 and some constantc> 0. This graph model is a variant of the so‐called configuration model, and includes heavy tail degrees with finite variance. The minimal number of edges between two arbitrary connected nodes, also known as the graph distance or the hopcount, is investigated whenN→ ∞. We prove that the graph distance grows like logνN, when the base of the logarithm equals ν = 𝔼[Dj(Dj− 1)]/𝔼[Dj] > 1. This confirms the heuristic argument of Newman, Strogatz, and Watts [Phys Rev E 64 (2002), 026118, 1–17]. In addition, the random fluctuations around this asymptotic mean logνNare characterized and shown to be uniformly bounded. In particular, we show convergence in distribution of the centered graph distance along exponentially growing subsequences. © 2005 Wiley Periodicals, Inc. Random Struct. Alg., 2005
Impact of new advances in seismology and geotechnical engineering on structural design since the Northridge earthquake
Authors: Lew Marshall , Acosta J. Adolfo
Published: March 2005

The Northridge earthquake has brought a decade of change in the practice of engineering for all structures, and for tall buildings in particular. With the earlier Loma Prieta earthquake in Northern California, there was already some impetus and momentum to improve seismic safety and reduce risks from seismic hazards. However, the extensive damage and economic losses from the Northridge earthquake fueled greater public will to meet the challenges and provide programs for the reduction of losses and human casualties. In the geotechnical engineering discipline, many of the advances involved a more consistent application of seismic risk across the United States in dealing with strong ground motions. Initiatives were set in place to develop seismic hazard models of the possible earthquake sources that affect the country and to use these models in developing design criteria for seismic design in all regions of the United States, not just in California. These ground motion estimates are now accounted for in the latest design guidelines and building codes; however, the treatments in these documents is simplified and not always tied to reality. Ground motions are complex and advances are being made to understand the complexities and explain the variations. Great advances in seismology have occurred in the 10 years since Northridge, and these advances will be incorporated into building design and analysis with time. Other advances have been made in the area of defining seismic hazards that result from ground failures in California. The Northridge and earlier earthquakes demonstrated that ground failures (especially related to soil liquefaction and landsliding) can present a significant risk and result in large losses. In the decade since the Northridge earthquake, structural analysis has advanced with leaps and bounds due to advances in computer software and hardware. Complex three‐dimensional analyses in the time domain once relegated to only large mainframe computers can now be performed on desktop computers in most structural engineering offices. To model the seismic behavior of structures more accurately, better modeling of the soil–structure interface as well as the soil has become necessary. Models incorporating the appropriate soil behavior provide for better understanding of the forces and displacements of the structures under seismic loading and possibly avoid overconservatism by not accounting for the soil behavior. Copyright © 2004 John Wiley & Sons, Ltd.
Strong evidence for gravity wave seeding of an ionospheric plasma instability
Authors: Nicolls Michael J. , Kelley Michael C.
Published: March 2005

Here we present evidence for gravity wave seeding of ionospheric plasma instabilities. On October 2, 2002 a series of magnetic substorms led to a large‐scale traveling ionospheric disturbance (LSTID) that was detected by the Arecibo incoherent scatter radar. Several large oscillations of the F layer occurred, including one that lifted the layer to over 450 km. At least two shorter period oscillations were identified in the plasma contours along the bottomside of the layer. The largest amplitude signal exhibited a downward phase velocity, vertical wavelength, and period (∼50 minutes) consistent with the linear theory of gravity waves. A ∼30‐minute period oscillation was amplified considerably when the bottomside was lifted to high altitudes near dawn. This amplification was likely due to a gravitational instability with a growth time of about 15 minutes. We believe that the LSTID created conditions conducive to instability, while the shorter period waves created the seed irregularities.