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51.
The purpose of this study was to determine whether aging alters neuronal uptake of norepinephrine (NE) in the rat heart and if dietary restriction influenced the effect of age on this system. Cardiac synaptosomes were prepared from 6-, 12- and 24-month-old male F344 rats fed ad libitum (AL) or a diet restricted (DR) to 60% of AL intake. Cardiac synaptosomes were incubated with 50, 100, 200, or 400 nM [3H]NE for 10 min at 37 degrees C with and without desmethylimipramine (DMI), a selective neuronal-uptake blocker. DMI-sensitive [3H]NE uptake was calculated as the difference between samples with and without DMI. NE uptake was adjusted for the number of cardiac synaptosomes in each sample by dividing by the endogenous NE content in each sample. The Vmax for uptake ([3H]NE/min/ng NE) declined significantly between 6 and 12 months in AL rats and between 12 and 24 months in DR rats. Km was not significantly different between age or diet groups. The change in Vmax with age suggests that the number of NE transporters per synaptosome may decline with age and that DR delays this effect of age. There were no differences in the sensitivity to DMI between age or diet groups.  相似文献   
52.
Good survival rates have been reported for resected early gastric adenocarcinoma (EGC) in patients found via screening procedures. However, the prevalence of Helicobacter pylori in EGC in unscreened populations is unclear. The major purpose of this investigation was to analyze the clinical experience and incidence of H. pylori in unscreened patients presenting with EGC at Charity Hospital over a 34-year period. From 1963 through 1997, the tumor registry at Charity Hospital compiled data on 2497 patients evaluated for gastric carcinoma. Of these patients, 26 (1%) had lesions that were confined to the mucosa or submucosa, i.e., T1N0M0 (American Joint Commission on Cancer classification). Pathology specimens and medical records were retrieved for confirmation of diagnosis and retrospective analysis for H. pylori. H. pylori was analyzed by Steiner staining and immunohistochemistry using a polyclonal antibody. EGC was detected in 12 men and 14 women with a mean age of 62 years. Upper gastrointestinal X-ray studies were performed on 19 of the 26 patients and failed to conclusively demonstrate a lesion in any case. Endoscopy was performed on 22 patients, and preoperative biopsies were positive in 95 per cent of these. Operative procedures included 2 local excisions and 22 subtotal and 2 total gastrectomies. No extended nodal dissections were performed. Microscopic evaluation revealed lesions limited to the mucosa in 63 per cent of cases and involving the submucosa in 37 per cent of the cases. Of the 14 patients evaluable of H. pylori, 79 per cent were positive for the bacterium. The status of 2 patients is unknown, and only 1 patient died of the original gastric cancer, for a disease-free survival of 96 per cent. The 5-year and 10-year overall survival rates were calculated to be 50 per cent and 21 per cent, respectively, when all causes of death were taken into consideration. Median follow-up of the survivors was 64 months. Resection of early gastric carcinoma in unscreened patients without extended lymphadenectomy yielded excellent results. H. pylori was present in 79 per cent of cases. These data suggest an association between H. pylori and EGC. Whether H. pylori infection is an etiologic factor in gastric cancer remains an area of active research.  相似文献   
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54.
A mosquito pathogenic strain of Bacillus sphaericus carried out the conjugal transfer of plasmid pAM beta 1 to other strains of its own and two other serotypes. However, it was unable to conjugate with mosquito pathogens from three other serotypes, with B. sphaericus of other DNA homology groups or with three other species of Bacillus. Conjugation frequency was highest with a strain having an altered surface layer (S layer). Conjugal transfer of pAM beta 1 was not detected in mosquito larval cadavers. B. sphaericus 2362 was unable to mobilize pUB110 for transfer to strains that had served as recipients of pAM beta 1. These observations suggest that it is unlikely that genetically engineered B. sphaericus carrying a recombinant plasmid could pass that plasmid to other bacteria.  相似文献   
55.
Adaptative changes in skeletal muscle following surface electrical stimulation (SES) were investigated in rhesus monkeys. SES was performed on the triceps brachialis muscle (TB) according to an intermittent pattern. The procedure was carried out for 3 wk, using a current with a medium frequency of 60 Hz normally observed in fast motor axons. The histochemical assays performed on biopsies taken from proximal and distal parts of the TB muscle, before and after the SES program, showed that the distribution of fibers typed by ATPase was unaffected. On the other hand, SES led to an overall increase in the mean fiber cross-sectional area (FCSA); P < 0.01 (+13.7%, NS, in proximal portion, vs +31%, P < 0.01 in distal portion). This increase in size occurred in all fiber types. SES was shown to induce an overall increase in capillary to fiber ratio (C/F; +11.06%, NS, in proximal portion, vs +25.93%, P < 0.05 in distal portion). The number of capillaries surrounding fiber Type II (CAFII) was significantly increased by SES (P < 0.05): +3.21%, NS, in proximal portion, versus +21.47%, P < 0.05 in distal portion. Moreover, the number of capillaries surrounding fiber Type I (CAFI) was statistically unaffected by SES. These results suggest that a stimulation of capillary growth may occur following SES-training. Citrate synthase activity was significantly increased after SES. This enhancement in oxidative potential was shown to occur in all fiber types (NADH-diaphorase staining).(ABSTRACT TRUNCATED AT 250 WORDS)  相似文献   
56.
We previously used fhuF as a sensitive reporter gene of the iron status of Escherichia coli. In this report, the fhuF gene was identified as open reading frame f262b at 99.2 min on the genome sequence map of E. coli K-12. The FhuF protein was labeled with a His-tag and then purified to electrophoretic homogeneity. Based on sulfur determinations and M?ssbauer and EPR spectroscopy, FhuF was identified as a [2Fe-2S] protein. The g values (gx = 1.886, gy = 1.961, gz = 1.994) and some of the M?ssbauer parameters of FhuF obtained [oxidized protein as isolated: delta EQ,4.2K = 0.474 mm s-1; Fe3+ (reduced protein): delta EQ = 0.978 mm s-1] are not typical of common [2Fe-2S] proteins and indicate that FhuF has unusual structural properties. The primary sequence of FhuF does not show any sequence similarities to known [2Fe-2S] proteins. By site-directed mutagenesis, each of the six cysteines of FhuF was replaced by serine. EPR of the six reduced mutant proteins revealed that the terminal cysteine residues 244, 245, 256, and 259 form the [2Fe-2S]Cys4 cluster. Mutants having the Cys-to-Ser replacement at positions 244, 245, 256, or 259 did not complement a fhuF mutant. The motif Cys-Cys-Xaa10-Cys-Xaa2-Cys in FhuF differs considerably from the motif Cys-Xaa2-Cys-Xaa9-15-Cys-Xaa2-Cys found in other [2Fe-2S] proteins. The unusual Cys-Cys terminal group of the cluster may explain the atypical EPR and M?ssbauer spectroscopic properties of the FhuF protein; possibly the tetrahedral symmetry at the ferric ion site is distorted. The phenotype of fhuF mutants and the structural features of the FhuF protein suggest that FhuF is involved in the reduction of ferric iron in cytoplasmic ferrioxamine B.  相似文献   
57.
The authors investigated development of the concept of division in young children. Experiment 1 examined whether children who can share are able to understand the inverse divisor–quotient relationship in partitive division tasks when asked to judge the relative size of 2 shared sets. Experiment 2 investigated whether young children understand the same inverse relation in quotitive tasks in which they were asked to judge the relative number of sets to be formed. The ability to compare share-outs and to take into account the inverse divisor–quotient relationship was present in approximately half of the 6-year-olds; age improvements were significant between 5 and 7 years. Partitive tasks, which are more similar to sharing, were easier than quotitive tasks, which seem to involve the coordination between sharing and part-whole concepts. This is evidence that children's initial understanding of division might be based on the action schema of sharing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   
58.
59.
Phytochemical compositions of five varieties of black soybeans (Glycine max) and their stabilities at room temperature, 4 and −80 °C over 14 months were determined by HPLC systems with electrochemical (ECD) and UV detectors. Polyphenol profiling was carried out by a liquid chromatography–electrospray ionisation-mass spectrometry (LC–ESI-MS) with orbitrap as a mass analyser in both positive and negative ion modes, and polyphenols in aglycone forms were quantified by HPLC–ECD. Five different varieties of black soybeans (G. max) contained 249–405 μg/g dry wt of γ-tocopherol and 6.76–14.98 μg/g dry wt of lutein. Major polyphenols in black soybeans (G. max) were daidzein (193–288 μg/g dry wt) and genistein (145–223 μg/g dry wt), mainly present as glucosides and acetyl glucosides. No significant decrease was found in total phenols of black soybeans (G. max) stored at room temperature, 4 or −80 °C for 14 months. On the other hand, lutein and γ-tocopherol degraded significantly within a month of storage at room temperature (p < 0.01), whereas they remained stable up to 6 months at 4 °C and up to 14 months at −80 °C. The current study indicates that black soybeans (G. max) are rich source of γ-tocopherol and phenols (isoflavones, flavonols, flavan-3-ols, proanthocyanidins and anthocyanin) and that the levels vary depending upon varieties. In addition, storage at low temperature is recommended to reduce the loss of fat-soluble phytochemicals in black soybeans (G. max) over an extended period of time.  相似文献   
60.
PPARγ agonist DIM‐Ph‐4‐CF 3 , a template for RXRα agonist (E)‐3‐[5‐di(1‐methyl‐1H‐indol‐3‐yl)methyl‐2‐thienyl] acrylic acid: DIM‐Ph‐CF3 is reported to inhibit cancer growth independent of PPARγ and to interact with NR4A1. As both receptors dimerize with RXR, and natural PPARγ ligands activate RXR, DIM‐Ph‐4‐CF3 was investigated as an RXR ligand. It displaces 9‐cis‐retinoic acid from RXRα but does not activate RXRα. Structure‐based direct design led to an RXRα agonist.

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