Consequences of Postnatally Elevated Insulin-Like Growth Factor-II in Transgenic Mice: Endocrine Changes and Effects on Body and Organ Growth.

Insulin-like growth factor-II (IGF-II) is an important regulator of embryonic growth and differentiation, but its function in postnatal life is unclear. To address this point, we generated transgenic mice harboring fusion genes in which a human IGF-II complementary DNA is placed under the transcriptional control of the rat phosphoenolpyruvate carboxykinase promoter. Transgene-specific messenger RNA was detected in liver, kidney, and several parts of the gut. Serum IGF-II levels in transgenic mice were 2-3 times higher than those in controls and increased after starvation. Circulating IGF-I correlated negatively and IGF-binding protein-2 (IGFBP-2) positively with IGF-II levels, suggesting that IGF-I is displaced from IGFBPs by IGF-II and that IGFII is a major regulator of IGFBP-2. Serum levels of IGFBP-3 and IGFBP-4 tended to be higher in phosphoenolpyruvate carboxykinase- IGF-II transgenic mice than in controls, as evaluated by ligand blot analysis. Starvation reduced serum IGF-I, but increased IGFBP-2 in transgenic mice more markedly than in controls. Fasting insulin levels were significantly reduced in transgenic mice, whereas glucose levels were not influenced by elevated IGF-II. The body growth of 4- and 12- week-old mice was not significantly influenced by elevated IGF-II, but transgenic mice displayed increased kidney and testis weight at the age of 4 weeks, and increased adrenal weight at the age of 12 weeks. Our results demonstrate that elevated IGF-II in postnatal life has multiple endocrine consequences and subtle time-specific effects on organ growth

Exploiting the HTX-Board as a Coprocessor for Exact Arithmetics

Certain numerical computations benefit from dedicated computation units, e.g. providing increased computation accuracy. Exploiting current interconnection technologies and advances in reconfigurable logic, restrictions and drawbacks of past approaches towards application-specific units can be overcome. This paper presents our implementation of an FPGA-based hardware unit for exact arithmetics. The unit is tightly integrated into the host system using state-of-the-art HyperTransport technology. An according runtime system provides OS-level support including dynamic function resolution. The approach demonstrates suitability and applicability of the chosen technologies, setting the pace towards broadly acceptable use of reconfigurable coprocessor technology for application-specific computing

Prostaglandin-independent protection by furosemide from oliguric ischemic renal failure in conscious rats

Prostaglandin-independent protection by furosemide from oliguric ischemic renal failure in conscious rats. In 38 conscious rats divided into seven groups, acute unilateral ischemic renal failure was induced by 1 hour of complete occlusion of the left renal artery while the contralateral kidney remained intact. Renal excretory function of the left kidney was monitored up to 144 hours after ischemia and revealed a typical course of oliguric renal failure with oligoanuria persisting for more than 48 hours. Urinary osmolality and sodium concentration became plasma isotonic after release of renal artery occlusion and approximated control values on day 6 after ischemia. In nine rats, the i.v. infusion of furosemide before (6 µg/min/100g body wt) and after (12 µg/min/ 100g body wt) renal artery occlusion protected the ischemic kidney from oligoanuria with endogenous creatinine clearance of 0.42 ± 0.11 ml/min/g kidney wt 5 hours after ischemia. Tubular absorption of sodium and water was at least partially preserved 36 hours after ischemia when infusion of furosemide was stopped. The loop diuretic significantly (P < 0.01) increased total urinary prostaglandin (PG) E2 excretion before and after renal artery occlusion; and 5 hours after ischemia, PGE2 excretion from the ischemic kidney significantly exceeded that from the intact kidney (P < 0.05). Indomethacin (1 mg/100g body wt) administered in six animals markedly suppressed control PGE2 excretion (P < 0.05) as well as the furosemide-induced rise in urinary PG excretion before and after ischemia but did not modify the protective effect of the diuretic in this experimental model. Inhibition of PG synthesis, however, reduced urinary flow rate and sodium and potassium excretion of the contralateral intact kidney and almost completely prevented its compensatory rise in creatinine clearance. The results indicate that mechanisms other than the intrarenal prostaglandin system must be considered to mediate the protective effects of furosemide in acute ischemic renal failure.Protection par le furosemide, indépendante des prostaglandins, de l'insuffisance rénale oligurique et ischémique chez le rat éveillé. Trente huit rats éveillés, répartis en sept groupes, ont été mis en insuffisance rénale aiguë ischémique unilatérale par occlusion complète de l'artère rénale gauche pendant 1 heure alors que le rein controlatéral était intact. La fonction excrétoire du rein a été surveillée pendant 144 heures après l'ischémie et elle a subi l'évolution typique de l'insuffisance rénale oligurique avec persistance de l'oligo-anurie pendant plus de 48 heures. L'osmolalité urinaire et la concentration de sodium sont devenues égales à celles du plasma après la levée de l'occlusion artérielle rénale et se sont rapprochées des valeurs contrôles au sixième jour après l'ischémie. Chez neuf rats la perfusion de furosemide avant (6 µg/min/100g poids corporel) et après (12 µg/ min/100g poids corporel) l'occlusion de l'artère rénale a protégé le rein ischémique de l'oligo-anurie, avec des clearances de la créatinine de 0,42 ± 0,11 ml/min/g de rein 5 heures après l'ischémie. La réabsorption tubulaire de sodium et d'eau était au moins partiellement préservée 36 heures après l'ischémie quand la perfusion de furosemide était arrêtée. Ce diurétique augmente significativement (P < 0,01) l'excrétion urinaire de prostaglan-dines (PG) E2 avant et après l'occlusion de l'artère rénale; 5 heures après l'ischémie l'excrétion de PGE2 par le rein lésé est significativement supérieure à celle du rein intact (P < 0,05). L'indométhacine (1 mg/100g poids corporel) administrée à six animaux diminue considérablement l'excrétion basale de PGE2 (P < 0,05) de même que l'augmentation, dépendante du furosémide, de l'excrétion urinaire de PG avant et après l'ischémie, mais ne change pas l'effet protecteur du diurétique dans ce modèle expérimental. L'inhibition de la synthèse de PG, cependant, diminue le débit urinaire et l'excrétion de sodium et de potassium du rein intact et empêche presque complètement l'augmentation compensatrice de la clearance de la créatinine. Ces résultats indiquent que d'autres mécanismes que le système des prostaglandines intrarénales doivent être invoqués comme médiateurs des effets protecteurs du furosémide dans l'insuffisance rénale aiguë ischémique

A lambda=3 mm molecular line survey of NGC1068. Chemical signatures of an AGN environment

We aimed to study the molecular composition of the interstellar medium (ISM) surrounding an Active Galactic Nucleus (AGN), by making an inventory of molecular species and their abundances, as well as to establish a chemical differentiation between starburst galaxies and AGN. We used the IRAM-30 m telescope to observe the central 1.5-2 kpc region of NGC1068, covering the frequencies between 86.2 GHz and 115.6 GHz. Using Boltzmann diagrams, we calculated the column densities of the detected molecules. We used a chemical model to reproduce the abundances found in the AGN, to determine the origin of each detected species, and to test the influence of UV fields, cosmic rays, and shocks on the ISM. We identified 24 different molecular species and isotopologues, among which HC3N, SO, N2H+, CH3CN, NS, 13CN, and HN13C are detected for the first time in NGC1068. We obtained the upper limits to the isotopic ratios 12C/13C=49, 16O/18O=177 and 32S/34S=5. Our chemical models suggest that the chemistry in the nucleus of NGC1068 is strongly influenced by cosmic rays, although high values of both cosmic rays and far ultraviolet (FUV) radiation fields also explain well the observations. The gas in the nucleus of NGC1068 has a different chemical composition as compared to starburst galaxies. The distinct physical processes dominating galaxy nuclei (e.g. C-shocks, UV fields, X-rays, cosmic rays) leave clear imprints in the chemistry of the gas, which allow to characterise the nucleus activity by its molecular abundances.Comment: 16 pages, 6 figures, 7 tables. Accepted for publication in Astronomy and Astrophysic

A general purpose HyperTransport-based Application Accelerator Framework

HyperTransport provides a flexible, low latency and high bandwidth interconnection between processors and also between processors and peripheral omponents. Therefore, the interconnection is no longer a performance bottleneck when integrating application specific accelerators in modern computing systems. Current FPGAs providing huge computational power and permit the acceleration of compute-intensive kernels. We therefore present a general purpose architecture based on HyperTransport and modern FPGAs to accelerate time-consuming computations. Further, we present a prototypical implementation of our architecture. Here we used an AMD Opteron-based system with the HTX Board [6] to demonstrate that common applications can benefit from available hardware accelerators. A cryptographic example showed that the encryption of files, larger then 50 kByte, can be successfully accelerated

Makroskopische Quasikristalle

Fünf Jahre ist es her, daß Dan Shechtman (Technion, Haifa) an der Metallegierung Al86Mn14 ein scharfes Elektronenbeugungsmuster mit Ikosaedersymmetrie fand. Weitreichende Ordnung, dokumentiert durch Bragg-Reflexe, und nicht-kristallographische Ikosaedersymmetrie mit fünfzähligen Achsen haben die Strukturphysiker in den Jahren seither veranlaßt, eine Fülle von Modellen für atomare Anordnungen zu entwickeln, die zwischen den periodischen klassischen Kristallen mit Fernordnung und den nur nahgeordneten amorphen Strukturen liegen. Erste Modellvorstellungen von Quasikristallen entnahm man den Penrose-Mustern. Sie bilden in zwei Raumdimensionen eine lückenlose Überdeckung der Ebene mit zwei Arten von Zellen in der Form einer spitzen und einer stumpfen Raute

Gravitation Research

Contains a summary of research.National Science Foundation (Grant MPS75-04033)M.I.T. Sloan Fund for Basic Researc

Lambda = 3 mm line survey of nearby active galaxies

We used the IRAM 30m telescope to observe the frequency range [86-116]GHz towards the central regions of the starburst galaxies M83, M82, and NGC253, the AGNs M51, NGC1068, and NGC7469, and the ULIRGs Arp220 and Mrk231. Assuming LTE conditions, we calculated the column densities of 27 molecules and 10 isotopologues. Among others, we report the first tentative detections of CH3CHO, HNCO, and NS in M82 and, for the first time in the extragalactic medium, HC5N in NGC253. Halpha recombination lines were only found in M82 and NGC253. Vibrationally excited lines of HC3N were only detected in Arp220. CH3CCH emission is only seen in the starburst-dominated galaxies. By comparison of the fractional abundances among the galaxies, we looked for the molecules that are best suited to characterise the chemistry of starbursts, AGNs and ULIRGs, as well as the differences among galaxies within the same group.Comment: 24 pages, 6 figures, 12 tables. Accepted for publication in Astronomy and Astrophysic