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  • 1990-1994  (10)
  • 1993  (10)
  • 1
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 128 (1993), S. 0 
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: ras mutations have been reported as an early event in some human malignancies and in the mouse skin model of multistep carcinogenesis; early studies in human non-melanoma skin cancers have reported variable rates of ras mutations. A recent study, however, has reported a high frequency of activating mutations of the Harvey-ras proto-oncogene in non-melanoma skin cancers, and the site specificity of the mutation at the second position of codon 12 prompted us to re-examine the importance of Ha-ras codon 12 mutations as an early event in the development of these tumours, using a combination of PCR and restriction fragment polymorphism of codon 12 of the Ha-ras gene. Dilution experiments confirmed that the method was sensitive and capable of detecting mutations at this codon when only 4% of the total alleles are mutated. We were surprised to find no mutations in the 40 basal cell carcinomas. 12 squamous cell carcinomas and 12 cases of Bowen's disease studied. We conclude that Ha-ras codon 12 mutations are rare events in human non-melanoma skin cancer in the U.K. The marked differences in the frequency of codon 12 Ha-ras mutations in published studies may relate to either technical artefacts, or differences in the molecular epidemiology between areas of low and high sun exposure.
    Materialart: Digitale Medien
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  • 2
    ISSN: 1365-2036
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Ranitidine bismuth citrate is a novel compound formed from ranitidine and a bismuth citrate complex. In conscious dogs, ranitidine bismuth citrate had similar activity to ranitidine hydrochloride as an inhibitor of histamine-induced gastric acid secretion when oral doses containing equivalent amounts of ranitidine base (0.1 or 0.3 mg/kg) were compared. In the rat, ranitidine bismuth citrate (3–30 mg/kg p.o.) prevented gastric mucosal damage induced by ethanol (fundic damage) and indomethacin (antral damage).Ranitidine hydrochloride and tripotassium dicitrato bismuthate were also effective against indomethacin induced damage, but were both significantly less potent than ranitidine bismuth citrate in this model.Ranitidine hydrochloride was inactive against ethanol-induced damage. In vitro, ranitidine bismuth citrate (1 mmol/L) inhibited human pepsin isoenzymes 1, 2, 3 and 5. Pepsin 1 was inhibited to a similar extent by ranitidine bismuth citrate, bismuth citrate and tripotassium dicitrato bismuthate at concentrations equivalent to 1 mmol/L bismuth, but ranitidine (1 mmol/L) was inactive. Ranitidine bismuth citrate was more potent than tripotassium dicitrato bismuthate as an inhibitor of pepsins 2, 3 and 5. Ranitidine bismuth citrate inhibited both Helicobacter pylori (effective concentration 4–32, μg bismuth/ml) and H. mustelae (1–4,μg bismuth/ml); similar results were obtained with tripotassium dicitrato bismuthate. Bismuth citrate was slightly less effective, and ranitidine hydrochloride was inactive (〉 125, μg/ml). In ferrets naturally colonized with H. mustelae, oral treatment with ranitidine bismuth citrate, 12 or 24 mg/kg twice daily for 4 weeks, caused a dose related clearance of H. mustelae. Qualitatively similar results were obtained in a small study with tripotassium dicitrato bismuthate and bismuth citrate.
    Materialart: Digitale Medien
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  • 3
    Digitale Medien
    Digitale Medien
    s.l. : American Chemical Society
    Journal of the American Chemical Society 115 (1993), S. 12096-12105 
    ISSN: 1520-5126
    Quelle: ACS Legacy Archives
    Thema: Chemie und Pharmazie
    Materialart: Digitale Medien
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  • 4
    Digitale Medien
    Digitale Medien
    Oxford, UK : Blackwell Publishing Ltd
    British journal of dermatology 129 (1993), S. 0 
    ISSN: 1365-2133
    Quelle: Blackwell Publishing Journal Backfiles 1879-2005
    Thema: Medizin
    Notizen: Extensive study of the p53 gene has established its role as a tumour-suppressor gene, and the involvement of mutant p53 in a wide spectrum of human malignancy. Many mutations of p53 result in a protein product that is abnormally stable, so that it becomes readily detectable by immunocytochemistry. In contrast, under normal conditions, it has been considered that levels of wild-type p53 were too low to be detectable. Although positive immunocytochemistry has been used as a marker of mutation, recent evidence suggests that this assumption may not always be valid. We have carried out both PCR-sequencing of exons 5-8 of the p53 gene in 20 basal cell carcinomas (BCC), and immunocytochemistry of these tumours with the anti-p53 antibody Do7. Twenty cases of Bowen's disease, in which we had previously documented mutations, were also immunostained. We report a low rate of p53 mutation in the BCCs we examined (2/20), and a discrepancy between tumours with positive immunostaining and those with mutation in both Bowen's disease and BCC. Of eight tumours in which we detected mutation, only four were immunopositive; of 19 immunopositive samples, only four showed detectable mutation. We discuss the implications of our results for the use of positive immunostaining in clinical diagnosis, and the involvement of p53 in skin carcinogenesis.
    Materialart: Digitale Medien
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  • 5
    ISSN: 1572-9680
    Schlagwort(e): root growth ; soil compaction ; aeration ; soil strength ; soil moisture
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Tree growth and soil physical properties were compared on two grazed plots planted with sycamore at 5 and 10 m square spacing on an upland Scottish site. Both plots received fertilizer and stocking density of ewes and lambs was adjusted to maintain a constant sward height. Mean tree height in 1990 and height increment (1988–90) were significantly greater in the 5 m spaced plot (P〈0.05). Although matric potential under the trees was generally greater than in the grassed rows between trees, mean penetration resistance (37–107 mm depth) was significantly greater (P〈0.01) under the trees. Even when the soil was close to field capacity, less than 10% of penetrometer readings were 〈 1 MPa under the trees, in comparison to 44% in grassed areas between trees. This demonstrates that surface compaction due to preferential treading by sheep near the base of trees was sufficient to have seriously reduced tree root growth. Penetration resistance under the 5 m spaced trees was significantly less (P〈0.05) than under the 10 m spaced trees. A technique for estimating the probability of root deflections by stones (in 35 mm depth intervals), Ps, from penetrometer readings was used. A significant relationship (P〈0.1) was found between tree height increment and depth to Ps≥0.4 in the 10 m plot.
    Materialart: Digitale Medien
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  • 6
    Digitale Medien
    Digitale Medien
    Springer
    Agroforestry systems 22 (1993), S. 17-24 
    ISSN: 1572-9680
    Schlagwort(e): Australian farming systems ; extension ; farmer attitudes ; revegetation ; policy vision
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract This paper discusses the extent to which Australian agriculture is integrating trees into farming systems and concludes that while broad environmental awareness and concern may have increased, Australian agriculture exemplifies essentially the same attitudes to native vegetation as those held by the first European settlers. It is suggested that for real change to occur, land users require three key ingredients — commitment, knowledge and resources. The state of play with respect to each of these key factors is reviewed and suggestions for reform mooted.
    Materialart: Digitale Medien
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  • 7
    ISSN: 1573-1561
    Schlagwort(e): Damson-hop aphid ; Phorodon humuli ; Homoptera ; Aphididae ; methyl salicylate ; (E)-2-hexenal ; β-caryophyllene ; semiochemicals ; aggregation ; attractant
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Biologie , Chemie und Pharmazie
    Notizen: Abstract Behavioral studies using an olfactometer demonstrated that spring migrants of the damson-hop aphid,Phorodon humuli, respond to semiochemicals released by spring migrants feeding on hop leaves. Samples of the total volatiles released on feeding were analyzed by coupled gas chromatographysingle cell recording techniques and showed the presence of several active components. Three compounds were identified, using coupled gas chromatography-mass spectrometry, as methyl salicylate, (E)-2-hexenal andβ-caryophyllene. These three compounds elicited responses from separate olfactory receptors on the antenna. In the olfactometer, both (E)-2-hexenal andβ-caryophyllene gave positive responses from spring migrants, and a mixture of the two compounds in the natural ratio was more attractive than (E)-2-hexenal alone. Addition of methyl salicylate eliminated the response to the active binary mixture.
    Materialart: Digitale Medien
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  • 8
    ISSN: 1573-5036
    Schlagwort(e): borescope ; minirhizotron ; pasture ; root length density ; silvopastoral ; wild cherry
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract A method for counting root intersections with observation tubes (mini- or micro-rhizotrons) is proposed that allows a theoretical conversion of root counts to estimated root length density and which is robust to the effects of tracking along the tubes. A field test showed that the method agreed well with measured root length densities in cores for wild cherry roots but not for roots of pasture species. The circumstances in which the method might be expected to perform well are discussed. Analysis of data from a field trial revealed that root counts were not uniformly distributed around the circumference of the observation tube. Implications for the design of such trials are noted.
    Materialart: Digitale Medien
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  • 9
    ISSN: 1573-5060
    Schlagwort(e): ODAP ; BOAA ; neurotoxin ; Lathyrism ; drought-tolerance ; toxicology ; interspecific-hybridization ; mutation breeding ; germoplasm collections
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Land- und Forstwirtschaft, Gartenbau, Fischereiwirtschaft, Hauswirtschaft
    Notizen: Abstract Efforts in grasspea (Lathyrus sativus) improvement have increased since the development of lines that are very low in the neurotoxin Beta-N-oxalyl-L-alpha-beta-diamino propionic acid (ODAP); also referred to as Beta-N oxalyl-amino-L-alanine (BOAA). Many programs now address several related aspects of improvement simultaneously. These include reduced ODAP concentrations, insect and disease resistance, nitrogen fixation, agronomic practices, fodder and forage production, and components for increased yielding ability. The coordinated, multidisciplinary approach now being applied to the genetic improvement of grasspea should allow the potential of this largely neglected grain legume to be fully realized.
    Materialart: Digitale Medien
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  • 10
    Digitale Medien
    Digitale Medien
    Springer
    Journal of low temperature physics 93 (1993), S. 907-919 
    ISSN: 1573-7357
    Schlagwort(e): 67.40.-w ; 67.40.Db ; 05.30.Jp
    Quelle: Springer Online Journal Archives 1860-2000
    Thema: Physik
    Notizen: Abstract We briefly review some general aspects of Bose condensation and off-diagonal long range order in infinite bulk systems and then discuss to what extent these features might be manifested in finite systems with free surfaces such as droplets of liquid 4 He at low temperatures. We focus on the structure of the one-body density matrix and the macroscopic wave function in the surface region, and note the possibility of a surface condensate.
    Materialart: Digitale Medien
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