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  • 1
    ISSN: 1432-1211
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Type of Medium: Electronic Resource
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  • 2
    ISSN: 1432-2323
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Description / Table of Contents: Résumé L'ulcère duodénal postérieur hémorragique est une complication majeure de la maladie uléreuse et grave surtout chez le sujet agé. Le traitement chirurgical doit s'efforcer d'obtenir une hémostase efficace et durable et éviter la formation d'une fistule du moignon duodénal. La difficulté majeure reste la fermeture du moignon duodénal. Dans cette série de 40 patients ayant eu une fermeture comprenant la dissection intramurale complétée d'un agrafage mécanique du moignon, il n'y a eu aucune récidive hémorragique ou fistule duodénale. Sept patients (17%) sont morts, dont trois d'une insuffisance respiratoire et deux d'une infuffisance hépatique.
    Abstract: Resumen La hemorragia por úlcera duodenal posterior es una complicación crítica, especialmente en pacientes de edad avanzada. El tratamiento quirúrgico debe lograr una hemostasia eficaz y estable y evitar el desarrollo de fístulas por escape a nivel del munón duodenal. La operación de escogencia parece ser la resección del antro y del píloro combinada con vagotomía troncular. Sin embargo, el cierre del duodeno puede ser diffícil. Se reporta el uso de un procedimiento de disección intramural del duodeno con cierre por medio del saturador automático en una serie de 40 pacientes, sin ningún caso de hemorragia recurrente ni de fístula duodenal. Siete pacientes (17%) murieron por causa de enfermedades concurrentes, especialmente insuficiencia respiratoria (3 pacientes) y falla hepática cirrótica (2 pacientes).
    Notes: Abstract Bleeding posterior duodenal ulcers is a critical problem espelally in patients of advanced age. Surgical treatment should obtain fficient and stable hemostasis and avoid digestive fistulas due to leakage if the duodenal stump. The main difficulty lies in the closure of the duodenal stump. A procedure using intramural dissection of the duodellum and closure by means of a stapler is reported for a series of 40 patients without recurrent bleeding or duodenal fistula. Seven patients (17%) died from associated diseases, especially respiratory insufficiency (3 patients) and cirrhotic liver failure (2 patients).
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  • 3
    ISSN: 1360-0443
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine , Psychology
    Notes: Aims  To compare data from the general population on intentionally reduced smoking and smoking cessation.Design  Longitudinal observation study.Setting  Northern German region.Subjects  Randomly sampled residents aged 18–64 (T1; n = 4075, response rate 70%). Daily cigarette smokers (n = 1520) were followed up after 30 (T2; n = 913) and 36 months (T3; n = 786).Measures  Self-reported smoking-related and socioeconomic variables. Participants were explicitly asked for reduction attempts (reducing cigarettes per day) and maintenance of reduction, which was defined independently of consumption measures.Findings  Between T1 and T2, reduction attempts (39%) were more frequent than quit attempts (33%), and according to self-report, reduction was more likely to be maintained for up to 12 months. Smokers maintaining reduction for up to 6 months had reduced their consumption at T3 by 34% compared with T2. Between T1 and T2, the occurrence of both a reduction and a quit attempt was most frequent (22%), followed by subjects exclusively trying to reduce (17%) and subjects exclusively trying to quit (4%). Subjects who exclusively tried to reduce had a significantly increased probability of further reduction attempts at T3 (OR = 4.4, 95% CI 2.0–10.1), while the probability of quit attempts was equal compared with subjects not attempting to reduce or quit (OR = 1.1, 95% CI 0.3–3.2). DSM-IV nicotine dependence was less common in subjects who exclusively tried to reduce. Other smoking-related and socioeconomic variables did not predict whether individuals attempted to reduce or attempted to quit.Conclusions  A considerable proportion of general population smokers attempt to reduce, and are able to maintain reduction of, cigarette consumption over time. Reduction attempts did not reduce the probability of a subsequent cessation attempt.
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  • 4
    ISSN: 0032-8332
    Keywords: Menstrual cycle ; Vaginal secretion ; Chemical signals ; Pheromones ; Social/physical contact ; Olfactory cues ; Crab-eating monkey ; Cynomolgus monkey ; Breeding husbandry
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract Twelve adult female crab-eating monkeys (Macaca fascicularis) were placed in six pairs of adjacent cages, allowing physical contact between members of these experimental pairs. Twelve additional females remained singly caged (no physical contact allowed) and served as six control “pairs.” In both experimental and control pairs, one member had a history of regular menstrual cycles, whereas the other tended to have cycles that were unusually long and/or irregular. Over a six-month period, menses and amount of vaginal secretion were recorded daily for all subjects, and the behavior of experimental pairs was sampled three times per week. During the course of the study, the irregular experimental subjects began to exhibit menstrual cycles of near normal length although there was no apparent trend to synchronize cycles. Irregular controls continued to show cycles that were abnormally long. Vaginal secretions tended to increase in all regularly cycling animals during days 9–15 (peak day 11) or reverse days 21–16 of the cycle, consistent with the estimated time of ovulation. Analysis of behavior indicated that irregularly cycling subjects inspected the genitalia of their regularly cycling cagemates at a significantly higher frequency than the converse (F=12.61,p〈.005), particularly during the follicular phase (F=3.39,p〈.07). These results suggest that close physical contact may serve to transmit chemical and/or hormonal cues that can normalize the menstrual cycle of crab-eating monkeys.
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  • 5
    ISSN: 1617-4623
    Keywords: Nitrate reductase ; cDNA expression cloning ; Tobacco ; Sequence ; Cytochrome b5
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Messenger RNAs encoding the nitrate reductase apoenzyme from tobacco can be translated in a cell-free system. Poly(A)+ mRNA fractions from the 23-32 S area of a sucrose gradient were used to build a cDNA library in the expression vector λgt11 with an efficiency of cloning of approximately 104 recombinants/ng mRNA. Recombinant clones were screened with a rabbit polyclonal antibody directed against the corn nitrate reductase, which cross reacts specifically with the nitrate reductases from dicotyledons. Among 240000 recombinant plaques, eight clones were isolated containing inserts of sizes ranging from 1.6 kb to 2.1 kb and sharing sequence homologies. Seven of these clones contained a common internal 1.6 kb EcoRI fragment. The identity of these clones was confirmed as follows. A fusion protein of 170 kDa inducible by IPTG and recognized by the rabbit nitrate reductase antibody was expressed by a lysogen derived from one of the recombinants. The antibodies binding the fused protein were eluted and shown to be inhibitory to the catalytic activity of tobacco nitrate reductase. Two monoclonal antibodies directed against nitrate reductase were also able to bind the hybrid protein. The 1.6 kb EcoRI fragment was sequenced by the method of Sanger. The open reading frame corresponding to a translational fusion with the β-galactosidase coding sequence of the vector shared strong homology at the amino acid level with the heme-binding domain of proteins of the cytochrome b5 superfamily and with human erythrocyte cytochrome b5 reductase. When the 1.6 kb EcoRI fragment was used as a probe for Northern blot experiments a signal corresponding to a 3.5 kb RNA was detected in tobacco and in Nicotiana plumbaginifolia mRNA preparations but no cross-hybridization with corn mRNAs was detected. The probe hybridized with low copy number sequences in genomic blots of tobacco DNA.
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  • 6
    ISSN: 1617-4623
    Keywords: Transposable element ; Nitrate reductase ; Nicotiana plumbaginifolia ; γ-Ray mutagenesis ; Nucleotide sequence
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Abstract By Northern blot analysis of nitrate reductase-deficient mutants of Nicotiana plumbaginifolia, we identified a mutant (mutant D65), obtained after γ-ray irradiation of protoplasts, which contained an insertion sequence in the nitrate reductase (NR) mRNA. This insertion sequence was localized by polymerase chain reaction (PCR) in the first exon of NR and was also shown to be present in the NR gene. The mutant gene contained a 565 by insertion sequence that exhibits the sequence characteristics of a transposable element, which was thus named dTnp1. The dTnp1 element has 14 by terminal inverted repeats and is flanked by an 8-bp target site duplication generated upon transposition. These inverted repeats have significant sequence homology with those of other transposable elements. Judging by its size and the absence of a long open reading frame, dTnp1 appears to represent a defective, although mobile, transposable element. The octamer motif TTTAGGCC was found several times in direct orientation near the 5′ and 3′ ends of dTnp1 together with a perfect palindrome located after the 5′ inverted repeat. Southern blot analysis using an internal probe of dTnp1 suggested that this element occurs as a single copy in the genome of N. plumbaginifolia. It is also present in N. tabacum, but absent in tomato or petunia. The dTnp1 element is therefore of potential use for gene tagging in Nicotiana species.
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  • 7
    ISSN: 1617-4623
    Keywords: Mutagenized protoplast cultures ; Nicotiana plumbaginifolia ; Nitrate-deficient mutants
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Two hundred and eleven nitrate reductase-deficient mutants (NR−) were isolated from mutagenized Nicotiana plumbaginifolia protoplast cultures by chlorate selection and regenerated into plant. More than 40% of these clones were classified as cnx and presumed to be affected in the biosynthesis of the molybdenum cofactor, the remaining clones being classified as nia mutants. A genetic analysis of the regenerated plants confirmed this proportion of nia and cnx clones. All mutants regenerated were found to carry monogenic recessive mutations that impaired growth on nitrate as sole nitrogen source. Mutants propagated by grafting on N. tabacum systematically displayed a chlorotic leaf phenotype. This chlorosis was therefore related to the NR deficiency. The observation of leaves with NR− chlorotic sectors surrounded by NR+ wild-type tissues suggeests that an NR deficiency is not corrected by diffusible factors. Periclinal chimeras between wild-type tobacco and the NR− graft were also observed. In this type of chimeric tissue chlorosis was no longer detectable when NR+ cells were in the secondmost (L2) layer, but was still detectable when NR− cells were in the secondmost layer. The genetic analysis of nia mutants revealed that they belong to a single complementation group. However three nia mutants were found to complement some of the other nia mutants. The apoenzyme of nitrate reductase was immunologically detected in several nia mutants but not in other members of this complementation group. Some of the nia mutants, although they were NR−, still displayed methylviologenitrate reductase activity at a high level. These data show that the nia complementation group corresponds to the structural gene of nitrate reductase. Some of the mutations affecting this structural gene result in the overproduction of an inactive nitrate reductase, suggesting a feedback regulation of the level of the apoenzyme in the wild type.
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  • 8
    ISSN: 1617-4623
    Keywords: Nicotiana tabacum ; Nitrate reductase ; Retrotransposon ; Transcription
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary The effects of Tntl retrotransposon insertion on nitrate reductase (NR) gene transcription have been analyzed in three NR-deficient insertional, mutants of Nicotiana tabacum. In the three mutants, named h9-Nia4, h9-Nia5 and h9-Nia6, Tnt1 was inserted into exon 3, exon 2 and exon 1 of the nia2 NR alloallelle, respectively. The mutants h9-Nia4 and h9-Nia6, which contained Tnt1 insertions that were oriented opposite to the direction of nia2 gene transcription, expressed chimaeric nia2-Tnt1 RNAs, respectively 12 kb and 10 kb long. The size observed in h9-Nia6 was close to the expected size for a full-length hybrid transcript starting and ending under the control of nia2 signals (about 9 kb). The larger transcript found in h9-Nia4 was shown to be due to a failure to splice the nia2 intron 2. The mutant h9-Nia5, which contained a Tntl insertion oriented in parallel with the direction of nia2 transcription expressed two truncated nia2-Tnt1 RNAs, 2 kb and 6.7 kb long. These transcripts arose from termination in the long terminal repeats (LTRs) of Tull. Since no full-length hybrid RNA was detected, we suggest that Tnt1 carries efficient termination signals, which are more efficiently recognized in the 3′ LTR than in the 5′ LTR.
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  • 9
    ISSN: 1617-4623
    Keywords: Nitrate reductase ; Reporter gene ; Nicotiana tabacum ; Nicotiana plumbaginifolia ; Transgenic plant
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology
    Notes: Summary Reporter gene techniques and mutant analysis were used to identify the molecular basis of the regulation of the expression of nitrate reductase (NR) by nitrate and nitrate-, or ammonium-derived metabolites (N-metabolites), in the true diploïd species Nicotiana plumbaginifolia and in the amphidiploïd species Nicotiana tabacum. The N. plumbaginifolia mutant E23 results from the insertion of a Tnt1-like retrotransposon (Tnp2) in the first exon of the single-copy nia gene, which encodes nitrate reductase. One of the resulting transcripts ends in the 5′ LTR (long terminal repeat) sequence of this retrotransposon, and another one in the 3′ LTR. Nitrate and N-metabolites modulate the expression of these truncated transcripts, indicating that intron splicing and termination processes are not essential to these regulatory events. A GUS reporter sequence was transcriptionally linked to the promoter of the nia-1 gene of N. tabacum. This fusion was functional in transient expression assays done with protoplasts derived from mesophyll cells of N. tabacum. However none of the regulatory mechanisms known to affect steady-state levels of the nia-1 transcript were operative under these experimental conditions. Transgenic plants carrying either this fusion or translational fusions of GUS linked to the promoter of either the nia-1 or nia-2 gene of N. tabacum were obtained by Agrobacterium-mediated transfer. A low proportion of the transgenic plants (22 out of 105 independent transformants) expressed GUS activity although at a low level. Only 4 plants exhibited a detectable level of GUS mRNA. The concentration of this mRNA increased significantly in an NR-deficient background, indicating regulation by N-metabolites. Only 2 plants, however, showed regulation (induction) by nitrate. Attempts to use aux2 or nptII reporter sequences linked to either the nia-1 or nia-2 promoter as marker genes for the selection of regulatory mutants of the nitrate assimilation pathway were unsuccessful because of our inability to isolate transgenic plants in which these reporter genes were properly regulated by nitrate. The implications of these results are discussed.
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  • 10
    ISSN: 1546-170X
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Medicine
    Notes: [Auszug] To the editor From an evolutionary perspective, the existence of many monogenic diseases is not intelligible. There is ongoing discussion as to what extent such disorders may be phenotypically balanced. Clear evidence exists indicating that certain red blood cell disorders are selected for by ...
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