| 1. |
- Amann, F., et al.
(författare)
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A search for murarregamma at the level of 10-13
- 1991
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Ingår i: Proceedings of the 25th International Conference on High Energy Physics. - 9810024347 ; , s. 1070-1071
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Konferensbidrag (refereegranskat)abstract
- The MEGA experiment, which is a search for the decay murarregamma with a branching ratio sensitivity of about 10-13, employs highly modular, fast detectors, state-of-the-art electronics, and a staged trigger with on-line filters. The detectors are contained in a 1.5-T solenoidal field produced by a superconducting magnet. Positrons are confined to the central region and are measured by a set of thin MWPCs. Photons are measured by one of four layers of pair spectrometers in the outer region. Most aspects of the design have been validated in engineering runs; data taking will begin in 1990 with much of the electron arm and one pair spectrometer layer installed.
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| 2. |
- Clavel, J., et al.
(författare)
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Steps toward determination of the size and structure of the broad-line region in active galactic nuclei. I. An 8 month campaign of monitoring NGC 5548 with IUE
- 1991
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Ingår i: Astrophysical Journal. - : American Astronomical Society. - 0004-637X .- 1538-4357. ; 366:1, s. 64-8181
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Tidskriftsartikel (refereegranskat)abstract
- The authors present emission-line and ultraviolet continuum observations of a type I Seyfert galaxy in which the time resolution is adequate for describing the character of variability. Using the IUE satellite, the nucleus of NGC 5548 was observed every 4 days for a period of 8 months. Its mean properties-continuum shape, line ratios-are not unusual for type I Seyfert galaxies, but it was found to be strongly variable. The ultraviolet continuum flux and broad emission line fluxes varied significantly, going through three large maxima and three deep minima. The great majority of all variations were well resolved in time. The data lend qualitative support to the view that photoionization by the nuclear continuum is responsible for driving the emission lines
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| 3. |
- Landin-Olsson, Mona, et al.
(författare)
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Immunoreactive trypsin(Ogen) in the sera of children with recent-onset insulin-dependent diabetes and matched controls
- 1990
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Ingår i: Pancreas. - : Ovid Technologies (Wolters Kluwer Health). - 0885-3177. ; 5:3, s. 241-247
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Tidskriftsartikel (refereegranskat)abstract
- To evaluate the exocrine pancreatic function at the time of diagnosis of insulin-dependent diabetes mellitus, we determined immunoreactive an-odal and cathodal trypsin(ogen) levels in sera from almost all children (n = 375) 0-14 years of age in Sweden in whom diabetes developed during 1 year, and in sex-, age-, and geographically matched control subjects (n = 312). The median level of anodal trypsin(ogen) was 5 (quartile range, 3-7) µg/L in children with newly diagnosed diabetes, compared with a median level of 7 (quartile range, 4-8) µg/L in control subjects (p < 0.0001). Similarly, the median level of cathodal trypsin(ogen) was 8 (quartile range, 4-10) µg/L in children with diabetes, compared with a median level of 11 (quartile range, 7-15) µg/L in control subjects (p < 0.0001). The median of the individual ratios between cathodal and anodal trypsin(ogen) was 1.4 in the diabetic patients and 1.7 in the control children (p < 0.001). In a multivariate test, however, only the decrease in cathodal trypsin(ogen) concentration was associated with diabetes. The levels of trypsin(ogen)s did not correlate with levels of islet cell antibodies, present in 81% of the diabetic children. Several mechanisms may explain our findings, for example, similar pathogenetic factors may affect both the endocrine and exocrine pancreas simultaneously, a failing local trophic stimulation by insulin on the exocrine cells may decrease the trypsinogen production, and there may be an increased elimination of trypsin(ogen) because of higher filtration through the kidneys in the hyperglycemic state.
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| 4. |
- Degerman, Eva, et al.
(författare)
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Single-step affinity purification, partial structure and properties of human platelet cGMP inhibited cAMP phosphodiesterase
- 1994
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Ingår i: Biochimica et Biophysica Acta. - 0006-3002. ; 1205:2, s. 189-198
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Tidskriftsartikel (refereegranskat)abstract
- The human platelet cilostamide- and cGMP-inhibited cAMP phosphodiesterase (cGI-PDE) was rapidly purified approximately 19,000-fold to apparent homogeneity using single step affinity chromatography on the isothiocyanate derivative of cilostamide coupled to aminoethyl agarose. Within 24 h, 30 micrograms of enzyme protein was obtained from 20 ml of packed platelets. Vmax for cAMP and cGMP was 6.1 and 0.9 mumol/min per mg protein, respectively. Several polypeptides (110/105, 79, 62, 55/53 kDa) were identified after SDS-PAGE, all of which were immunologically related to cGI-PDE and represented approx. 5, 20, 50 and 20% of the total protein, respectively. Limited proteolysis of the cGI-PDE with chymotrypsin produced a major fragment of approximately 47 kDa (and at least two smaller peptides) with catalytic activity and sensitivity to cGMP and OPC 3911 similar to controls. Phosphorylation of the cGI-PDE by cAMP-dependent protein kinase (A-kinase) resulted in maximal incorporation of 0.6-1.8 mol of 32P/mol 110/105 and 79 kDa polypeptides; much lower and variable amounts of phosphate were incorporated into the 62 and 55/53 kDa polypeptides. After digestion of cGI-PDE with several proteinases a number of peptides were isolated and sequenced. Most of the peptide sequences obtained could be aligned within the carboxy terminal domain of the deduced sequence of the human cardiac cGI-PDE. These and other results suggest that the subunit size of the intact platelet cGI-PDE is 110 kDa and that proteolytic fragments of 79, 62 and 55/53 kDa are produced during purification. The smaller fragments (62 and 55/53 kDa) contain the catalytic domain; the larger fragments (110 and 79 kDa) also contain the regulatory domain with phosphorylation sites for A-kinase.
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| 5. |
- Faldon, M. E, et al.
(författare)
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Studies of time-resolved harmonic generation in intense laser fields in xenon
- 1992
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Ingår i: Journal of the Optical Society of America B: Optical Physics. - 0740-3224. ; 9:11, s. 2094-2099
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Tidskriftsartikel (refereegranskat)abstract
- We report preliminary experimental and computational studies of the temporal evolution of the harmonics, generated in xenon, by 50-ps pulses from a Nd: YLF laser, amplified in Nd: glass amplifiers, and focused to produce intensities in the range 1013--5 {\texttimes} 1013 W cm{\textminus}2. Measurements were made of the temporal profiles of the seventh- and ninth-order harmonics using a specially modified VUV streak camera with better than 7-ps temporal resolution. These results were compared with predictions of a numerical model that included the effects of neutral atom depletion and photoelectron dispersion in the calculation of the harmonic output as a function of time.
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| 6. |
- Bjornsson, E. S., et al.
(författare)
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Effects of hyperglycemia on interdigestive gastrointestinal motility in humans
- 1994
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Ingår i: Scand J Gastroenterol. - 0036-5521. ; 29:12, s. 1096-104
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Gastrointestinal motility disorders are common in patients with diabetes mellitus. Recent studies indicate that hyperglycemia can affect gastric emptying and gastric motility in healthy subjects and diabetics. METHODS: The effect of acute hyperglycemia on gastrointestinal motility was studied with a manometric technique in healthy subjects. Seven individuals, four men and three women, 23-34 years old, were studied on 2 different days. On 1 of the days a 5-h registration was performed after an overnight fast. On another day and after an initial basal period, acute steady-state hyperglycemia was induced by intravenous glucose infusion for 90 min. Motility variables were evaluated in four segments: in the gastric antrum, the proximal duodenum, the distal duodenum, and the proximal jejunum. RESULTS: Fasting migrating motor complex rhythm including migration of phase III prevailed during hyperglycemia. Compared with euglycemia, the motility index in phase II was lower during hyperglycemia in all segments studied. In the antrum the difference was 62% (p < 0.01); in the proximal duodenum, 37% (p < 0.01); in the distal duodenum, 44% (p < 0.05); and in the jejunum, 58% (p < 0.01). During hyperglycemia the prevalence of propagated contractions in phase II was significantly lower than during euglycemia both in the antrum and the proximal duodenum. In the last part of phase III in proximal duodenum most individual contractions were propagated in orad direction compared with early phase III, and this difference persisted during hyperglycemia. The number of long clusters was significantly increased during hyperglycemia as compared with euglycemia: 2.0 +/- 0.6 per hour versus 0.4 +/- 0.14 (p < 0.01). In late phase II plasma levels of motilin and pancreatic polypeptide were significantly decreased during hyperglycemia. CONCLUSION: Hyperglycemia not only reduces the motility in the stomach but also inhibits motility in both the duodenum and the jejunum. The results show that acute hyperglycemia has an important impact on small-intestinal motility.
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| 7. |
- Bornfeldt, Karin E.
(författare)
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Actions and interactions of insulin-like growth factor-I and insulin in vascular smooth muscle
- 1991
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Insulin-like growth factor-I (IGF-I) is a polypeptide with structural and biological similarities with insulin, and the receptors for IGF-I and insulin are homologous. The present investigation was devoted to the actions and interactions of IGF-I and insulin in vascular smooth muscle. In vascular smooth muscle from intact arteries and in cultured vascular smooth muscle cells there are abundant IGF-I receptors, but very few insulin receptors. IGF-I and insulin stimulated proliferation of cultured vascular smooth muscle cells, and the effects were probably mediated via the IGF-I receptor. However, the maximal growthpromoting effect of IGF-I was twice the maximal effect of insulin. If an acidic amino acid was substituted for the basic amino acid histidine in insulin B-chain (BlO His:::} Asp), like in IGF-I, the maximal growth-promoting activity reached the effect of IGF-1. The amino acid in position 10 in insulin B-chain may thus be important for the growthpromoting activity of insulin. Vascular smooth muscle cells express IGF-1 mRNA and produce imm1,1noreactive IGF-1 in vitro. Levels of IGF-1 m RNA were decreased by platelet-derived growth factor (PDGF-BB), basic fibroblast growth factor (bFGF) and serum, whereas IGF-1 and high concentrations of insulin increased IGF-I rnRNA and immunoreactive IGF-I. It is thus possible that IGF-1 is able to increase its own production in an autocrine loop withpositive feedback. The growth-promoting effects of IGF-1 and insulin were weak compared to the effects ofPDGF-BB and bFGF. The results indicate qualitative as well as quantitative differences between IGF-1 and insulin compared to PDGF-BB and bFGF. IGF-1 gene expression in aortic tissue was found to be decreased by diabetes and fasting in vivo, and the levels were restored if diabetic rats were treated with insulin. Vascular smooth muscle proliferation induced by balloon catheterization was found to be impaired by diabetes and increased by insulin-treatment in vivo, although not to the levels in normal rats. IGF-1 stimulated vascular smooth muscle proliferation in diabetic rats in vivo without affecting the diabetic state, and IGF-I gene expression was increased in proliferating vascular smooth muscle. The results suggest that IGF-I is involved in vascular smooth muscle proliferation in vivo. In conclusion, insulin is less potent than IGF-1 in stimulating proliferation of vascular smooth muscle, and the growth-promoting effects of insulin are weaker than the effects ofiGF-1, suggesting that insulin in concentrations found in plasma has little direct effect on vascular smooth muscle proliferation. IGF-1 is probably of importance for vascular smooth muscle proliferation, and the results suggest that IGF-1 can be locally produced and regulated in the vascular wall.
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| 8. |
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| 9. |
- Maguire Jr., Gerald Q., et al.
(författare)
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Graphics applied to medical image registration
- 1991
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Ingår i: IEEE Computer Graphics and Applications. - : IEEE. - 0272-1716 .- 1558-1756. ; 11:2, s. 20-27
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Tidskriftsartikel (refereegranskat)abstract
- Software that has been developed to automate and standardize comparison of 3D images is discussed. The major approaches to image registration are examined. The authors' registration and reconstruction software is described. Studies carried out to determine the relative accuracy of the present registration methods are reported. The main goal of the authors is to improve on commercial SPECT reconstruction algorithms and provide quantification accuracy sufficient for numerical assessment of tracer distribution.
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| 10. |
- Meacci, E, et al.
(författare)
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Molecular cloning and expression of human myocardial cGMP-inhibited cAMP phosphodiesterase
- 1992
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Ingår i: Proceedings of the National Academy of Sciences. - 1091-6490. ; 89:9, s. 3721-3725
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Tidskriftsartikel (refereegranskat)abstract
- We have cloned a cDNA for a myocardial cGMP-inhibited cAMP phosphodiesterase (cGI PDE) from a human heart cDNA library in lambda Zap II. The open reading frame [3.5 kilobases (kb)] of cDNA clone n.13.2 (7.7 kb) encodes a protein of 125 kDa. In Northern blots of total human ventricle RNA, a single mRNA species (8.3 kb) hybridized with a 4-kb EcoRI restriction fragment of clone n.13.2 cDNA (containing the entire open reading frame). The carboxyl-terminal region of the deduced amino acid sequence of the cGI PDE contains the putative catalytic domain conserved among mammalian PDE families. A partial cDNA clone, n.2, encoding a truncated, 54-kDa cGI PDE containing the conserved domain was expressed as a catalytically active fusion protein in Escherichia coli. cAMP hydrolytic activity was inhibited by cGMP and OPC 3911 but not by rolipram. Thus, this report provides direct proof that the conserved domain contains the catalytic core of cGI PDEs.
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