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  • 1
    Electronic Resource
    Electronic Resource
    Alterations in Msx 1 and Msx 2 expression correlate with inhibition of outgrowth of chick facial primordia induced by retinoic acid (1997)
    Springer
    Anatomy and embryology 195 (1997), S. 203-207 
    Details
    ISSN: 1432-0568
    Keywords: Key words Epithelial-mesenchymal interactions ; Chick embryo ; Homeobox-containing gene ; Facial morphogenesis ; Facial defect
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Spatially-restricted expression domains of Msx 1 and Msx 2 in the developing chick face suggest that they may play a role in epithelial-mesenchymal interactions governing outgrowth of facial primordia. Retinoid application to developing chick faces reproducibly inhibits upper beak outgrowth but the lower beak is unaffected. In the normal face, high levels of Msx gene transcripts in upper and lower beak primordia correlate with regions of outgrowth. Following retinoid treatment, Msx 1 and Msx 2 transcripts are rapidly down-regulated in upper beak primordia where outgrowth is inhibited, but remain largely unchanged in lower beak primordia, where outgrowth is unaffected. Decreases in gene expression precede retinoid-induced morphological changes in the upper beak, suggesting that Msx gene products are involved in mediating the effect of retinoids on facial development.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s004290050039
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  • 2
    Electronic Resource
    Electronic Resource
    Renal abscesses: appearance on gadolinium-enhanced magnetic resonance images (1996)
    Springer
    Abdominal imaging 21 (1996), S. 172-176 
    Details
    ISSN: 1432-0509
    Keywords: Key words: Kidney, abscess〈+〉—〈+〉Kidney, infection〈+〉—〈+〉Kidney, magnetic resonance imaging〈+〉—〈+〉Kidney, computed tomography.
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract. Purpose: To determine the appearance of renal abscesses on gadolinium-enhanced magnetic resonance (MR) images, we reviewed 12 MR studies of eight patients with renal abscesses. These findings were compared with findings on other imaging modalities. Methods: Eight patients underwent 12 MR studies at 1.5 T, including T1-weighted gradient echo and fat-suppressed spin echo pre- and post-Gd-DTPA enhancement. Two radiologists retrospectively reviewed the MR images and compared MR findings to the findings on contrast-enhanced computed tomography (CECT) in five patients, noncontrast computed tomography (NCCT) in two patients, and ultrasound in all patients. Results: On contrast-enhanced MR images, renal abscesses were clearly depicted as heterogeneously low-signal-intensity lesions. Four patients had solitary abscesses, and four had multiple abscesses. Prominent perinephric inflammatory stranding was observed in six patients and was best shown on gadolinium-enhanced T1 fat-suppressed images. CECT findings were comparable to contrast-enhanced MR images, although contrast resolution was less on CECT images in all cases. Renal abscesses were poorly shown on NCCT and ultrasound images. Conclusion: Renal abscesses are clearly shown on gadolinium-enhanced MR images as low-signal-intensity lesions associated with prominent perinephric inflammatory strands. In this study, NCCT and ultrasound studies are poor at defining abscesses. Despite lesser contrast resolution of CECT versus MRI, the findings in cases of renal abscesses are similar. In patients with elevated serum creatinine, iodine contrast allergy, or the need for serial exams, MRI may be the best imaging technique to evaluate renal abscesses.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002619900038
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  • 3
    Electronic Resource
    Electronic Resource
    Transitional cell carcinoma of the upper urinary tract: staging by MRI (1995)
    Springer
    Abdominal imaging 20 (1995), S. 365-367 
    Details
    ISSN: 1432-0509
    Keywords: Kidney ; MR, 81.1214 ; Kidney, neoplasm, 81.31, 81.21 ; Magnetic resonance (MR), contrast enhancement
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract Background This study evaluates the ability of MRI to stage transitional cell carcinoma of the upper urinary tract. Methods Nine patients who had transitional cell carcinoma of the upper urinary tract detected by other imaging modalities underwent MRI examination at 1.5 T. Imaging included pre- and postgadolinium-DTPA T1-weighted images (9 patients) pre- and postgadolinium chelate T1-weighted fat-suppressed spin echo (7 patients). Postcontrast images were acquired prior to the presence of gadolinium within the collecting system (〈2 min postcontrast), intermediate (2.5–8 min), and late (〉10 min) postcontrast. Images were prospectively interpreted and lesion staging was determined. Correlation with histopathology was obtained in all cases. Results Transitional cell cancers were demonstrated in 9/9 patients, and tumors ranged in size from 2 to 8 cm (mean = 3.8 cm) in one dimension. Correct tumor staging was performed in 8/9 patients. The staging error in one case occurred because direct tumor extension into the renal parenchyma was not detected. Conclusions The results of this preliminary study show that MRI stages transitional cell cancers relatively well; however, MRI is not able to detect superficial invasion of renal parenchyma.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00203373
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  • 4
    Electronic Resource
    Electronic Resource
    Active salinity choice and enhanced swimming endurance in 0 to 8-d-old larvae of diadromous gobies, including Sicydium punctatum (Pisces), in Dominica, West Indies (1995)
    Springer
    Marine biology 121 (1995), S. 409-417 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract We studied the early life history of diadromous gobies in Dominica, West Indies, from May 1989 to May 1991, emphasising Sicydium punctatum Perugia. The transition of newly hatched larvae from upriver nest sites to the sea was studied in laboratory experiments. Newly hatched larvae are negatively buoyant but avoid settling to the bottom by active swimming during drift to the sea. Laboratory experiments evaluated salinity preferences and effects on swimming endurance. Larvae in haloclines actively selected low to intermediate salinities. Initially (0 to 5-d post-hatch), larvae minimized exposure to salinities 〉10 ppt, but later (5 to 8-d) occupied increasingly saline water. Larvae in no-choice freshwater or seawater treatments ceased activity at 4 to 5 d, but in haloclines larvae remained active up to 8 d post-hatch. Salinities 〈10 ppt are important for early survival of sicydiine gobies. Implications for larval survival and transport are discussed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349450
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  • 5
    Electronic Resource
    Electronic Resource
    Habitat use by juvenile Atlantic cod (Gadus morhua) in the presence of an actively foraging and non-foraging predator (1995)
    Springer
    Marine biology 123 (1995), S. 421-430 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Experiments were conducted in the autumn and winter of 1992/93 to examine habitat use by juvenile (age 0+) Atlantic cod, Gadus morhua L., before, during and following exposure to a passive or actively foraging predator (age 3+ cod). Experiments presented groups of juvenile cod (n=5 fish/group) with one of two combinations of three substrates; (1) gravel, sand, and a patch of artificial kelp (“kelp”), or (2) cobble, sand, and kelp. Cobble is known to provide juvenile cod with a refuge from predation. Kelp was used to test the hypothesis that juvenile cod associate with fleshy macroalgae in nature because of the safety it provides from predators. There was little difference in habitat use by juvenile cod before, during or following exposure to a passive predator. Under these conditions, juvenile cod appeared to prefer finer grained mineral substrates and avoided the kelp. The extent of the juvenile response to a passive predator was to avoid the predator's location in the experimental tank. In contrast, juvenile cod showed a significant shift in habitat use when exposed to an actively foraging predator, hiding in cobble or, when cobble was not available, in kelp. Use of both these habitats resulted in a significant reduction in predation risk to the juvenile cod. Our results suggest that: (1) an association with kelp provides safety from predation to juvenile cod, and (2) juvenile cod are capable for assessing the risk a predator represents and adjust their response accordingly.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00349220
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  • 6
    Electronic Resource
    Electronic Resource
    Changes in phospholipase A2 activity and lipid content during early development of Atlantic halibut (Hippoglossus hippoglossus) (1998)
    Springer
    Marine biology 130 (1998), S. 369-376 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract During early development in fish, phospholipase A2 (EC 3.1.1.4) regulates membrane lipid modifications, which relates to changes in environmental conditions and provision of fatty acids required for metabolic energy substrates and prostaglandin biosynthesis. A method to analyze phospholipase A2 in rat tissues has been modified to measure its activity in embryonic Atlantic halibut (Hippoglossus hippoglossus L.). Egg and embryo samples were collected during the 1994 spawning season. Enzyme activity was undetectable at fertilization but in 10-d embryos was 230 pmol mg−1 h−1 (at 20 °C) and increased by ∼120% at hatch (17-d). Significant alterations in the fatty acid composition of important phospholipids, phosphatidylcholine (PC) and phosphatidylethanolamine (PE), were also observed. The content of some critical polyunsaturated fatty acids, and the ratio of unsaturated/saturated fatty acids, declined significantly over development. Acyl-chain restructuring mediated through the activity of phospholipase A2, coupled with other observed lipid changes (significant increases in the PC/PE ratio and cholesterol content), would produce a decreased fluidity of membranes during embryonic development, coinciding with the predicted upward movement of larvae in the water column. Arachidonic acid (20:4n-6) removed from PE could serve as a precursor for biosynthesis of 2-series prostaglandins, and eicosapentaenoic acid (20:5n-3) from PC is a likely source for other prostaglandin types. Despite removal of polyunsaturated fatty acids, there was an overall increase in lipid and fatty acid concentration, which can be attributed to amino acid catabolism during early developmental stages.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050257
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  • 7
    Electronic Resource
    Electronic Resource
    Variation in condition of coastal Newfoundland 0-group Atlantic cod (Gadus morhua): field and laboratory studies using simple condition indices (1999)
    Springer
    Marine biology 133 (1999), S. 611-620 
    Details
    ISSN: 1432-1793
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Demersal 0-group Atlantic cod (Gadus morhua L.) were collected in Trinity Bay, Newfoundland, Canada, between August 1993 and January 1994. Diet composition and simple indices of condition (hepato-somatic index, condition factors and body ash content) were determined. Laboratory experiments were also conducted to determine whether simple indices of condition reflect differences in energy intake (ration level) and to determine minimum index of condition values, assessed from 0-group cod that died due to exhaustion of their energy reserves. Determination of lower critical indices of condition provided a meaningful interpretation of field data on feeding, condition and survival of 0-group cod. In the wild, indices of condition reflecting variation in liver and muscle energy reserves of cod increased rapidly with the consumption of Calanus finmarchicus, which exhibited a high incidence of oil sacs, and declined abruptly when this lipid-rich prey was no longer consumed. Liver and muscle condition of 0-group cod from the field varied seasonally, but their condition was consistently above that of cod that died in the laboratory. Laboratory studies, using three ration levels, revealed that condition indices differed over time and among ration levels. Indices of condition representing variation in muscle energy reserves exhibited a steady decline once the hepato-somatic index fell below about 2.0. We interpret this as evidence for depletion of lipids first and then proteins, a pattern similar to that of larger juveniles and adults. We conclude that as long as 0-group cod are above a “safe” level of condition their body length can still increase even when condition is declining.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002270050501
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  • 8
    Electronic Resource
    Electronic Resource
    Effects of chitin amendment of soil on microorganisms, nematodes, and growth of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.) (1996)
    Springer
    Biology and fertility of soils 22 (1996), S. 221-226 
    Details
    ISSN: 1432-0789
    Keywords: Chitin ; Heterodera trifolii ; Meloidogyne spp. ; Nematodes ; Nodulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Geosciences , Agriculture, Forestry, Horticulture, Fishery, Domestic Science, Nutrition
    Notes: Abstract Effects of soil amendment with crabshell chitin on the growth of white clover (Trifolium repens L.) and perennial ryegrass (Lolium perenne L.), and on populations of soil bacteria, fungi, and plant-parasitic and free-living nematodes were investigated in a pot trial. Five soil samples were collected from Te Puke (Paengaroa Shallow Sand, a Typic Hapludand) and five from Hamilton (Bruntwood silt loam, an Aquic Hapludand), New Zealand. Subsamples of each soil were either amended with chitin or unamended and planted with white clover and ryegrass. The ryegrass shoot weight in amended soil was greater (P〈0.01), most probably due to N mineralised from chitin. A significantly lower (P〈0.01) root: shoot ratio of ryegrass in the amended soil also suggested improved N availability, and therefore less root mass was needed to support a given shoot mass. A reduction in nodulation was observed in 12-day-old white clover seedlings (P〈0.05) and also in 6-week-old seedlings (P〈0.01). The shoot weight of white clover was significantly lower (P〈0.05) in amended soil, possibly due to phytotoxic effects of chitin. Chitin increased (P〈0.01) the populations of bacteria and fungi by 13-fold and 2.5-fold, respectively. The cyst nematode of white clover, Heterodera trifolii, was significantly reduced in chitin-amended soil, possibly due to increased levels of chitinase produced by rhizosphere microorganisms. Two other plant-parasitic nematodes, Pratylenchus spp. and Tylenchus spp., were also reduced in ryegrass roots and in soil as a result of the chitin amendment. However, the total number of free-living nematodes increased 5.4-fold in amended soil.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00382516
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  • 9
    Electronic Resource
    Electronic Resource
    An investigation of point defects in silicon carbide (1995)
    Springer
    Applied physics 61 (1995), S. 55-58 
    Details
    ISSN: 1432-0630
    Keywords: PACS: 61.70; 68.55; 78.70
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics , Physics
    Notes: Abstract.  Positron lifetime measurements on bulk samples of single crystal SiC wafers have shown that both 6H and 4H polytypes exhibit a bulk lifetime of 150±2 ps. All samples contained a second, defect-related lifetime component, ranging in value from 250 to about 300 ps with rather low intensities. The defect structure exhibited by the nanocrystalline samples is, not unexpectedly, much more complex. Positron beam experiments on Electron Cyclotron Resonance Chemical Vapour Deposited (ECR-CVD) SiC thin films showed that the positrons are very sensitive to changes in important film parameters as a function of the deposition conditions. It was found that the film density is lower than expected, probably due to hydrogen incorporation; variations in composition among different films were detected through variations in the S parameters, and differences were observed in the electric field at the film–substrate interface due to hydrogen passivation of dangling bonds and different substrate resistivities.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01538211
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  • 10
    Electronic Resource
    Electronic Resource
    Relative potency of controlled-release oxycodone and controlled-release morphine in a postoperative pain model (1999)
    Springer
    European journal of clinical pharmacology 55 (1999), S. 425-429 
    Details
    ISSN: 1432-1041
    Keywords: Key words Oxycodone ; Morphine ; Controlled-release formulation
    Source: Springer Online Journal Archives 1860-2000
    Topics: Chemistry and Pharmacology , Medicine
    Notes: Abstract Objective: The relative analgesic potency of single doses of oral controlled-release oxycodone and oral controlled-release morphine were compared in a randomized, double-blind trial using a postoperative pain model. Methods: Women (n = 169) with moderate to severe pain following abdominal hysterectomy received single oral doses of controlled-release oxycodone, 20 mg or 40 mg, or controlled-release morphine, 45 mg or 90 mg. Assessments were made at 30 min, 60 min, then hourly after dosing for 12 h or until remedication. Results: The most precise estimates of relative potency showed that controlled-release oxycodone was 1.8 times more potent than controlled-release morphine for total effect (95% confidence limits 1.09–2.42; lambda 0.44) and 2.2 times more potent for peak effect (95% confidence limits 0.96–4.59; lambda 0.71). Controlled-release oxycodone at doses of 20 mg or 40 mg was comparable with controlled-release morphine at doses of 45 mg or 90 mg, respectively, for total and peak analgesic effects. For the two higher doses, time to peak relief was approximately 1 h shorter with controlled-release oxycodone than with controlled-release morphine. Most patients reported onset of analgesia within 1 h with all doses. Side effects were similar with the two opioids. Conclusion: Oral controlled-release oxycodone was twice as potent as oral controlled-release morphine in this single-dose, relative potency assay. When converting patients from oral morphine to oral oxycodone, an initial oral oxycodone dose of one-half the oral morphine dose is recommended.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002280050651
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