1,671 research outputs found
Nonlinear dispersive three-dimensional finite-difference time-domain analysis for photonic-crystal lasers
No full textThe three-dimensional finite-difference time-domain method that can handle dispersive and dynamic nonlinear-gain media is proposed and realized. The effect of carrier diffusion is included through the laser rate equations. Through this three-dimensional nonlinear gain FDTD method, rich laser-dynamics behaviors, such as the lasing threshold, the relaxation oscillation, and the spatial hole burning, are directly observed from a hexapole mode. (c) 2005 Optical Society of America.This work was supported in part by MOST under the National R&D Project for Nanoscience
and Technology and by the MIC-IITA under the ITRC-20050C1090-0502-0b029 program
Short term growth hormone (GH) treatment of GH-deficient adults increases body sodium and extracellular water, but not blood pressure
No full textInitiation of GH treatment in adults is frequently complicated by the development of symptomatic fluid retention. To investigate the mechanism and extent of fluid retention that occurs with dosages of GH used in the treatment of GH-deficient adults, we conducted a double blind study in which seven GH-deficient patients (aged 24-74 yr) each received in random order daily sc injections of placebo, a physiological dose of GH (0.04 U/kg, low dose), and a supraphysiological dose of GH (0.08 U/kg, high dose) for 7 days, separated by 21-day washout periods. On the seventh day, measurements were made of serum insulin-like growth factor I, body weight, exchangeable sodium, plasma volume, angiotensinogen, PRA, aldosterone, atrial natriuretic peptide (ANP), and mean 24-h ambulatory heart rate and blood pressure. GH significantly increased mean insulin-like growth factor I levels from 105 ± 11 to 304 ± 45 μg/L during low dose treatment (P = 0.006) and 400 ± 76 μg/L during high dose treatment (P = 0.004). High dose GH caused a 1.2 ± 0.3 kg increase in body weight (P = 0.01) and a 193 ± 65 mmol increase in exchangeable sodium (P = 0.008). Low dose GH had a lesser effect, with no significant increase in body weight, but an increase in exchangeable sodium of 113 ± 37 mmol (P = 0.02). Plasma volume was not significantly affected by GH treatment. Mean supine angiotensinogen levels were significantly higher during both GH treatments compared to placebo (low dose, P = 0.017; high dose, P = 0.028) as were mean supine pRA levels (low dose, P = 0.0002; high dose, P = 0.0025). Supine angiotensin II, aldosterone, and ANP levels were not significantly affected by GH treatment. There was no significant change from placebo in any of the sodium-regulating hormones in the erect posture. The mean 24-h heart rate was significantly higher during low dose (82 ± 2 beats/min; P = 0.0001) and high dose (88 ± 3 beats/min; P = 0.0001) GH treatment than during placebo (67 ± 3 beats/min). However, no significant change in mean 24-h systolic or diastolic blood pressure was observed. In summary, acute GH administration using doses currently employed in treating adults causes a dose-related increase in body weight and body sodium, but no associated increase in blood pressure. We conclude that 1) sodium retention is a physiological effect of GH, but does not cause an acute rise in blood pressure; and 2) the mechanism of sodium and fluid retention is not primarily due to enhanced aldosterone secretion or inhibition of ANP release, but more likely to a direct renal tubular effect
Early in vitro induction of rat pituitary GH mRNA by T31.
No full textPrevious work has shown that thyroid hormone stimulates rat pituitary GH synthesis and GH mRNA activity and concentration. However, the earliest demonstration of increase in GH mRNA activity was 24 hours following T3 addition whereas stimulation of GH synthesis has been observed 2 hours after treatment with T3. Thus, it is unknown whether increase in pituitary GH mRNA is a prerequisite for the stimulation of GH synthesis. In the present investigation in vitro addition of 1.5 x 10(-10) M T3 to pituitaries isolated from hypothyroid rats resulted in a slight but significant increase of GH mRNA activity within 2 hours. Further stimulation of GH mRNA activity was observed over the period of 12 hours. No increase of GH mRNA activity occurred in the absence of T3, and T3 had no effect on the PRL mRNA activity. These findings suggest that increase in GH mRNA may be responsible for the observed induction of GH synthesis, and that at least one of the primary actions of thyroid hormone is at the nuclear level.In VitroJournal ArticleResearch Support, U.S. Gov't, P.H.S.SCOPUS: ar.jinfo:eu-repo/semantics/publishe
RNAseq analysis of fast skeletal muscle in restriction-fed transgenic coho salmon (Oncorhynchus kisutch) : an experimental model uncoupling the growth hormone and nutritional signals regulating growth
No full textBackground Coho salmon (Oncorhynchus kisutch) transgenic for growth hormone (Gh) express Gh in multiple tissues which results in increased appetite and continuous high growth with satiation feeding. Restricting Gh-transgenics to the same lower ration (TR) as wild-type fish (WT) results in similar growth, but with the recruitment of fewer, larger diameter, muscle skeletal fibres to reach a given body size. In order to better understand the genetic mechanisms behind these different patterns of muscle growth and to investigate how the decoupling of Gh and nutritional signals affects gene regulation we used RNA-seq to compare the fast skeletal muscle transcriptome in TR and WT coho salmon. Results Illumina sequencing of individually barcoded libraries from 6 WT and 6 TR coho salmon yielded 704,550,985 paired end reads which were used to construct 323,115 contigs containing 19,093 unique genes of which >10,000 contained >90 % of the coding sequence. Transcripts coding for 31 genes required for myoblast fusion were identified with 22 significantly downregulated in TR relative to WT fish, including 10 (vaspa, cdh15, graf1, crk, crkl, dock1, trio, plekho1a, cdc42a and dock5) associated with signaling through the cell surface protein cadherin. Nineteen out of 44 (43 %) translation initiation factors and 14 of 47 (30 %) protein chaperones were upregulated in TR relative to WT fish. Conclusions TR coho salmon showed increased growth hormone transcripts and gene expression associated with protein synthesis and folding than WT fish even though net rates of protein accretion were similar. The uncoupling of Gh and amino acid signals likely results in additional costs of transcription associated with protein turnover in TR fish. The predicted reduction in the ionic costs of homeostasis in TR fish associated with increased fibre size were shown to involve multiple pathways regulating myotube fusion, particularly cadherin signaling.Peer reviewe
GH and the cardiovascular system: an update on a topic at heart
No full textIn this review, the importance of growth hormone (GH) for the maintenance of normal cardiac function in adult life is discussed. Physiological effects of GH and underlying mechanisms for interactions between GH and insulin-like growth factor I (IGF-I) and the cardiovascular system are covered as well as the cardiac dysfunction caused both by GH excess (acromegaly) and by GH deficiency in adult hypopituitary patients. In both acromegaly and adult GH deficiency, there is also increased cardiovascular morbidity and mortality possibly linked to aberrations in GH status. Finally, the status of the GH/IGF-I system in relation to heart failure and the potential of GH as a therapeutic tool in the treatment of heart failure are reviewed in this article. © 2014 The Author(s)
Murine amniotic fluid stem cells contribute mesenchymal but not epithelial components to reconstituted mammary ducts
No full textIntroduction: Amniotic fluid harbors cells indicative of all three germ layers, and pluripotent fetal amniotic fluid stem cells (AFSs) are considered potentially valuable for applications in cellular therapy and tissue engineering. We investigated whether it is possible to direct the cell fate of AFSs in vivo by transplantation experiments into a particular microenvironment, the mammary fat pad. This microenvironment provides the prerequisites to study stem cell function and the communication between mesenchymal and epithelial cells. On clearance of the endogenous epithelium, the ductal tree can be reconstituted by the transfer of exogenously provided mammary stem cells. Analogously, exogenously provided stem cells from other tissues can be investigated for their potential to contribute to mammary gland regeneration. Methods: We derived pluripotent murine AFSs, measured the expression of stem cell markers, and confirmed their in vitro differentiation potential. AFSs were transplanted into cleared and non cleared fat pads of immunocompromised mice to evaluate their ability to assume particular cell fates under the instructive conditions of the fat-pad microenvironment and the hormonal stimulation during pregnancy. Results: Transplantation of AFSs into cleared fat pads alone or in the presence of exogenous mammary epithelial cells caused their differentiation into stroma and adipocytes and replaced endogenous mesenchymal components surrounding the ducts in co-transplantation experiments. Similarly, transplantation of AFSs into fat pads that had not been previously cleared led to AFS-derived stromal cells surrounding the elongating endogenous ducts. AFSs expressed the marker protein α-SMA, but did not integrate into the myoepithelial cell layer of the ducts in virgin mice. With pregnancy, a small number of AFS-derived cells were present in acinar structures. Conclusions: Our data demonstrate that the microenvironmental cues of the mammary fat pad cause AFSs to participate in mammary gland regeneration by providing mesenchymal components to emerging glandular structures, but do not incorporate or differentiate into ductal epithelial cells
OsEIN2 is a positive component in ethylene signaling in rice
No full textEIN2 is a central signal transducer in the ethylene-signaling pathway, and a unique membrane-anchored protein. By screening a cDNA library, we have isolated a cDNA clone (OsEIN2) that encodes the rice EIN2 homolog. The full-length ORF clone was obtained by reverse transcriptase-polymerase chain reaction. OsEIN2 shares significant amino acid sequence similarity with Arabidopsis EIN2 (57% similarity and 42% identity). Both the numbers and positions of introns and exons in the OsEIN2 and AtEIN2 coding regions are also conserved. To address whether this structural similarity is indicative of functional conservation of the corresponding proteins, we also generated transgenic lines expressing the antisense construct of OsEIN2. Those plants were stunted and shoot elongation was severely inhibited. Their phenotypes were similar to that found with wild-type rice seedlings that were treated with AgNO3, an ethylene signal inhibitor. In the OsEIN2 antisense plants, the expression levels of two ethylene-responsive genes, SC129 and SC255, were decreased compared with the wild types. These results suggest that OsEIN2 is a positive component of the ethylene-signaling pathway in rice, just as AtEIN2 is in Arabidopsis. Our antisense transgenic plants produced approximately 3.5 times more ethylene than the wild-type plants. Expression analysis of rice ACS and ACO genes showed that the transcript levels of OsACS1 and OsACS1 were elevated in the transgenic plants.X1156sciescopu
Book Review: Comrades Betrayed: Jewish World War I Veterans Under Hitler
No full textThis is a pre-copyedited, author-produced version of an article accepted for publication in [German History] following peer review. The version of record [Grady, T. (2021). [Review of the book Comrades Betrayed: Jewish World War I Veterans Under Hitler by M. Geheran]. German History, 39(3), 478–479] is available online at: https://academic.oup.com/gh/article/39/3/478/6308748Book review of Comrades Betrayed: Jewish World War I Veterans Under HitlerUnfundedAAM out of embargo 24/06/2023, output uploaded to CR 30/01/202
Espressione genica indotta dall'ormone somatotropo nei monociti di bambini sani e con deficit di GH
No full text2018 - 2019Somatotropic hormone (GH) has transcriptional effects on the cells of many organs, directly by activating its receptor (GHR) or indirectly through induction of IGF-1 or other mediators. The presence of GHR in almost all cellular tissues makes GH action systemic even if, to date, still not well characterized. The immune system is among the districts where the effect of the somatotropic hormone is documented by mechanisms that are still poorly understood.The primary objective of this study is to determine the transcriptional effect of GH on peripheral blood monocytes. These cells were chosen for the significant expression of GHR on their surface and because they are easily accessible. Although the transcriptional response to somatotropic hormone is specific tissue, the study of the effects of GH on monocytes can serve as a model for other cell types and highlight differences between healthy subjects and those with GH deficiency (GHD).The diagnosis of GHD, during the developmental age, is classically based on the clinical evaluation associated with radiological and laboratory investigations (GH-IGF-1 axis stimulus test). Although provocation tests represent diagnostic gold standard, they have poor reproducibility and accuracy and are characterized by a considerable number of false positives and sometimes negatives.The secondary objective of this study is to identify differential transcriptional profiles between healthy subjects and with GHD.For this purpose, the gene expression of monocytes from healthy children and with GHD was compared in culture, under basal conditions and after stimulation with recombinant GH (rh-GH).Two groups of 12 subjects were selected, group S: healthy male children with normal height and growth rate and group D: children of the same sex and age and suffering from GHD, not yet in replacement therapy. Peripheral blood monocytes were purified by subtraction with monoclonal antibodies and the purity level was determined by laminar flow cytofluorimetry with monoclonal antibodies. Monocytes were grown for 24 hours with and without rh-GH. Total RNA was extracted and frozen until the analysis was performed simultaneously for all the experimental points using the Next Generation Sequencing methodology on Illumina platform. Differential expression of mRNA was analyzed by comparing the monocytes of healthy children and with GHD, stimulated in culture with rh-GH or not stimulated: GHD not stimulated (D-CNTR) vs healthy not stimulated (S-CNTR); healthy non-stimulated (S-CNTR) vs healthy stimulated (S-GH); non-stimulated GHD (D-CNTR) vs stimulated GHD (D-GH); GHD stimulated (D-GH) vs healthy stimulated (S-GH).The analysis between D-CNTR vs S-CNTR groups identified 58 genes with differential expression. Furthermore, 23 genes were modulated by GH in healthy children and 4 genes in children with GHD. Differential analysis between D-GH vs S-GH groups, on the other hand, identified 150 genes with differential expression.Finally, analysis performed by Ingenuity Pathway Analysis software showed a significant increase in NFAT immune pathways and dendritic cell maturation and a consistent increase in the expression of dendritic markers (HLA-A, HLA-C, CCR7) in monocytes of children with GHD compared to healthy children, after stimulation in culture with recombinant GH.In conclusion, the results of this study have demonstrated a clear transcriptional effect of GH on monocytes, direct and indirect through intermediate mediators, suggesting to evaluate the pro-inflammatory status of children with growth hormone deficiency more in depth.Furthermore, this study identified a gene expression profile of monocytes in children with GHD which, once verified in a larger number of patients, could represent an alternative to stimulus tests and guide the diagnosis of GH deficiency.Finally, our study opens future perspectives in order to identify a transcriptional profile or specific genes specific to GHD condition. [edited by Author]XXXII cicl
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