共查询到20条相似文献,搜索用时 0 毫秒
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In primary human diploid fibroblasts, infection with an unpurified stock of human cytomegalovirus induced accumulation of the CC chemokine MCP-1 in the cell culture medium. By 24 h postinfection, the level of MCP-1 returned to that in uninfected cultures. When cells were infected with UV-inactivated human cytomegalovirus, the induction of MCP-1 was still observed, but no reduction was seen by 24 h postinfection or later. This effect was the result of a decrease in the level of MCP-1 mRNA present within the infected cell. Infection with purified virus revealed that the induction of MCP-1 was due to an activity found in the medium of infected cells; purified virions did not induce the expression of MCP-1. However, infection with purified virions repressed the level of MCP-1 mRNA below that found in uninfected cells. Additionally, infection with human cytomegalovirus prevented the induction of MCP-1 expression by tumor necrosis factor alpha and interleukin-1beta. The CC chemokine receptor encoded by the human cytomegalovirus US28 open reading frame (ORF) did not appear to play a role in this process, since a mutant virus in which the US28 ORF had been deleted downregulated MCP-1 in the same manner. 相似文献
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PURPOSE: This article presents a new optimization method for stereotactic radiosurgery treatment planning for gamma unit treatment system. METHODS AND MATERIALS: The gamma unit has been utilized in stereotactic radiosurgery for about 30 years, but the usual procedure for a physician-physicist team to design a treatment plan is a trial-and-error approach. Isodose curves are viewed on two-dimensional computed tomography (CT) or magnetic resonance (MR) image planes, which is not only time consuming but also seldom achieves the optimal treatment plan, especially when the isocenter weights are regarded. We developed a treatment-planning system on a computer workstation in which Powell's optimization method is realized. The optimization process starts with the initial parameters (the number of isocenters as well as corresponding 3D isocenters' coordinates, collimator sizes, and weight factors) roughly determined by the physician-physicist team. The objective function can be changed to consider protection of sensitive tissues. RESULTS: We use the plan parameters given by a well-trained physician-physicist team, or ones that the author give roughly as the initial parameters for the optimization procedure. Dosimetric results of optimization show a better high dose-volume conformation to the target volume compared to the doctor's plan. CONCLUSION: This method converges quickly and is not sensitive to the initial parameters. It achieves an excellent conformation of the estimated isodose curves with the contours of the target volume. If the initial parameters are varied, there will be a little difference in parameters' configuration, but the dosimetric results proved almost to be the same. 相似文献
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In vivo administration of an antisense oligonucleotide targeted toward the D2 dopamine (DA) receptor mRNA (D2 AS) markedly inhibited D2 receptor-mediated behaviors but produced only a relatively small reduction in the levels of D2 DA receptors in mouse striatum. This apparent dissociation between DA receptor-mediated behaviors and the levels of D2 DA receptors was addressed by inhibiting the total number of D2 DA receptors by intraperitoneal administration of the selective, irreversibly acting D2 DA receptor antagonist fluphenazine-N-mustard (FNM) and then determining the effects of D2 AS, administered intracerebroventricularly, on the rate of synthesis of D2 DA receptors and on the recovery of D2 receptor-mediated behaviors. FNM inactivated approximately 90% of D2 DA receptors within 4 hr of treatment, after which the receptors returned to normal levels by approximately 8 days. D2 AS treatment significantly inhibited the rate of recovery of D2 DA receptors in striatum of FNM-treated mice. FNM treatment also produced a number of behavioral alterations, including catalepsy, and the inhibition of stereotypic behavior induced by the D2/D3 DA receptor agonist quinpirole. Both of these behaviors returned to normal within 8 days after FNM treatment. D2 AS treatment delayed the restoration of these FNM-induced behaviors. Thus, it reduced the rate of disappearance of the cataleptic behavior induced by FNM and significantly delayed the restoration of the stereotypic behavior induced by quinpirole. The changes induced by D2 AS on D2 receptor-mediated behaviors were reversed on cessation of D2 AS treatment. A random oligomer given in the same amount and for the same length of time as that of the D2 AS had no significant effects on either D2 DA receptor synthesis or DA receptor-mediated behaviors. These studies demonstrate that in vivo administration of D2 AS decreased the rate of recovery of D2 DA receptors and inhibited the recovery of D2 DA receptor-mediated behaviors after irreversible receptor inactivation and suggest that D2 AS treatment inhibits the synthesis of a functional pool of D2 DA receptors. 相似文献
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KL Thorpe P Gorman C Thomas D Sheer J Trowsdale S Beck 《Canadian Metallurgical Quarterly》1997,200(1-2):177-183
3,5-Dihydroxy-4-isopropylstilbene (ST), an antibiotic produced by the bacterial symbiont Photorhabdus luminescens of the nematodes of the genus Heterorhabditis was determined quantitatively in nematode bacterium-infected insects using HPLC or TLC for separation and UV for quantification. Comparable and reproducible results were obtained with both HPLC-UV and TLC-UV methods. Several factors, including solvents for extraction of the antibiotic from the infected insects, eluents for TLC development and programs for HPLC operation, were investigated. Of the four solvents used, namely acetone, methanol, ethyl acetate and diethyl ether, acetone had the highest extraction efficacy, and the ST recovery rate was about 95%. ST can be easily separated from all other bacterial metabolites on a TLC plate using a mixture of chloroform-methanol (98.5:1.5) or by HPLC using acetonitrile and water as the mobile phase. 相似文献
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Possibilities of studying the properties of a selective gene pool structure, a new characteristic of the population genetic structure, are described. The characteristic depends on the type of selection and its effects on individual genes. The selective structure is evaluated by estimating significant differences between the interpopulation variation of i genes (FST(i)) and the average variation of the total gene pool (FST). This allows the role of individual genes in the selective gene pool structure to be determined and a hypothesis on the effect of the selection proposed, thus, providing a possibility of comparing individual genes and gene pools in terms of the effects of the natural selection, the key microevolutionary factor. The authors also describe properties and a reliable estimation of FST(i) and FST, possibilities and factors of estimating a selection-neutral differentiation F(e) from genetic demographical data and the empirical average FST of gene markers (classical, DNA, quasi-genetic), stability of genetic processes and other aspects of using an equality FST = F(e) = 1/[4NeMe + 1], construction of a representative sample of a populations with regard to their hierarchic structure, gene sampling and polymorphism, etc. FST(i) values for gene pools of indigenous populations from various continents and various regions of northeast Eurasia were estimated (> 90 alleles, > 30 loci). For all polymorphic genes (0.05 < or = q < or = 0.95), the average FST x 10(2) was 1.60 in Europe, 8.01 in Asia, 6.63 in Africa, 6.34 in Australia, 11.34 in America, and 6.78 in northeast Eurasia. Regional gene pools of the latter displayed FST of 2.25 in the European part, 2.62 in the Caucasus, 3.55 in the Urals, 2.71 in Central Asia and Kazakhstan, and 8.02 in Siberia and the Russian Far East. 相似文献
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BACKGROUND: Sonic muscle fibers intrinsic to the swim bladder of the oyster toadfish Opsanus tau proliferate throughout adult life and have an unusual radial morphology: alternating ribbons of sarcoplasmic reticulum (SR) and myofibrils surround a central core of sarcoplasm. Large fibers in adults form multiple cores, fragment, and appear to divide into smaller, more energy efficient units. METHODS: We examined embryonic to adult development of sonic muscle using electron and light microscopy and focused on the incidence of satellite cells (SC). RESULTS: Muscle fibers form late in the larval period from myoblasts, which do not appear to fuse into myotubes, but enlarge and differentiate myofibrils in a single patch. The SR differentiates from the outside inward, separating the myofibrils into bundles of varying thickness, which often exceed the thickness seen in adults. SCs in juveniles and adults have a sparse cytoplasm and a heterochromatic nucleus. The % SC nuclei (SC nuclei/total nuclei) decreases from a high of 88% in larvae to a low of 1% in adults although the adult average is 10%. No embryonic type fibers in the process of differentiating myofibrils were seen in adults. Small immature fibers, which had not yet formed the central core, have a complete radially organized contractile cylinder. CONCLUSIONS: Immature muscle fibers formed embryonically in the larval period have a different morphology from immature fibers in adults, suggesting that splitting rather than SCs is a major source of new fibers in adults. 相似文献
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During Blattella germanica embryo development, the nutritive yolk protein vitellin is processed by a cysteine protease, which is activated proteolytically from a proprotease during acidification of yolk granules. A murine polyclonal antiserum was generated with the purified proprotease as the immunogen. The antiserum was made monospecific to proprotease by subtractive affinity chromatography using proprotease-free yolk proteins as ligand. The purified antibodies were employed to investigate the temporal and spatial expression of the proprotease during vitellogenesis and embryo development. Anti-proprotease-reactive peptides appeared in extracts of fat bodies and ovarian follicles of post-mating females, but not in fat bodies of males or the fat bodies or follicles of unmated females, suggesting that the proprotease is synthesized extraovarially. Use of the antibodies was extended to monitor the kinetics of proprotease disappearance during early embryo development. 相似文献
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N Arsic T Rajic S Stanojcic PN Goodfellow M Stevanovic 《Canadian Metallurgical Quarterly》1998,83(1-2):139-146
The effects of nimodipine, a calcium channel blocker, on noise-induced hearing loss were examined in gerbils. Animals were implanted subcutaneously with a timed-release pellet containing either nimodipine (approximately 10 mg/kg/day) or placebo and exposed to either 102 or 107 dBA noise. Serum levels were tested in two subjects and were in the range known to protect humans from cerebral artery vasospasm and ischemia-related neurologic deficits. Nimodipine and control groups had similar amounts of noise-induced (a) permanent threshold shift; (b) reductions in distortion product otoacoustic emissions; (c) reductions in tuning and suppression of the compound action potential; and (d) loss of outer hair cells. The results suggest that nimodipine, at a dose which results in clinically relevant serum levels, does not provide protection from the effects of moderately intense noise exposures. 相似文献
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Fenspiride inhibits the calcium signal evoked by the inflammatory peptide formyl-Met-Leu-Phe (fMLP) in peritoneal macrophages, but at concentrations (approximately 1 mM) far above the therapeutic range (approximately 1 microM). Here, in rat alveolar macrophages, high fenspiride concentrations (1 mM) were required to inhibit the calcium signals evoked by the calcium agonist Bay K8644 or by ionomycin. Moreover, fenspiride (1 mM) was a poor inhibitor of the cell membrane depolarization induced by gramicidine D. By contrast, fenspiride blocked Na+-H+ antiport activation by (i) fMLP with an IC50 = 3.1 +/- 1.9 nM and (ii) PMA (phorbol 12-myristate 13-acetate) with an IC50 = 9.2 +/- 3.1 nM. Finally, protein kinase C (PKC) activity of macrophage homogenate was not significantly modified by 10 or 100 microM fenspiride (at 100 microM: 2.57 +/- 1.60 vs. 2.80 +/- 1.71 pmol/10(6) cells/min). In conclusion, fenspiride inhibits fMLP- and PMA-induced pH signals in rat alveolar macrophages, probably by acting distally on the PKC transduction signal. This pH antagonistic action may be relevant for the antiinflammatory mechanism of fenspiride and requires further investigation. 相似文献
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FM Hisama J Oshima CE Yu YH Fu J Mulligan SM Weissman GD Schellenberg 《Canadian Metallurgical Quarterly》1998,52(3):352-357
OBJECTIVE: The audiologic presentation of vestibular schwannoma (VS) associated with neurofibromatosis type 2 (NF2) has not been well characterized. The goal of this study was to investigate the audiologic features of NF2-associated VS and to determine their relationship to the size of the tumor. STUDY DESIGN: A retrospective case review. SETTING: Quaternary governmental medical research institute evaluating patients fitting specific criteria for ongoing clinical studies. PATIENTS: Audiologic and magnetic resonance imaging data were available for 40 patients (25 males, 15 females), with an average age of 32 years, who had been recruited for ongoing clinical and genetic studies of NF2. MAIN OUTCOME MEASURES: The audiologic profile and magnetic resonance imaging characteristic of tumor were retrospectively reviewed. RESULTS: The average size of the tumor at presentation was 7.26 +/- 16.58 cm3 and measured 1.2, 1.6, and 1.1 cm in the anterior/posterior, lateral/medial, and superior/inferior dimensions, respectively. An increase in lateral/medial size of the tumor most significantly correlated with deterioration in mid- (1,000-2,000 Hz) and high- (4,000-8,000 Hz) frequency hearing levels, elevated speech reception threshold, and prolonged auditory brain stem response waves III and V latency. CONCLUSIONS: Patients with NF2 demonstrate a more predictable audiologic profile for a given size tumor than has been previously described with spontaneous or sporadic VS. 相似文献
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IuG Rychkov OV Zhukova EV Ogryzko IuV Shne?der 《Canadian Metallurgical Quarterly》1998,34(8):1138-1150
New data on the association of the state of health and the disease incidence with the gene pool were obtained in the East European population. The second principal component (PC2.G, 11.4% of the total variance) of the geographic variation in the gene pool (100 alleles of 34 loci) showed a distinct latitudinal dependence corresponding to the natural zonality of Eastern Europe. This was also characteristic of the first principal component (PC1.M, 75.6% of the total variance) of the geographic variation in the disease incidence (i.e., the number of all new cases diagnosed in out-patient clinics per year) in the rural population. The disease incidence decreased from the south-southeast to the north-northwest in European Russia. The coefficient of the geographic pairwise correlation between PC2.G and PC1.M was r = 0.945; their specific correlation remained high (r = 0.864), even after a correction for the effects of age composition and heterozygosity. Thus, an insignificant variation in the gene pool was shown to significantly affect the geographic distribution of disease incidence in the East European population of Russia (eta 2 = 0.892). A correlation of mapped geographic distributions of PC1.M and PC2.G in the modern population with those of the principal components of the geographic variation of the late Paleolithic material culture in Eastern Europe was analyzed. The origin of the latitudinal zonality of the modern gene pool was dated back to the late Pleistocene-early Holocene. A conclusion was made that diseases that affected reproduction and lethality in the Paleolithic population still represent a mechanism of the gene pool's adaptation to the natural zonality of the environment. The latitudinal zonality of disease incidence, which was characteristic of the ancient population, is conserved in the today's population, owing to the gene pool. 相似文献
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Leptin is an adipocyte hormone involved in the regulation of energy homeostasis. Generally accepted biological effects of leptin are inhibition of food intake and stimulation of metabolic rate in ob/ob mice, that are defective in the leptin gene. In contrast to these centrally mediated effects of leptin, we are reporting here on leptin effects on glucose incorporation into lipids and glucose decarboxylation in adipocytes isolated from male lean albino rats. Adipocytes previously cultivated (15 h) in the presence of leptin presented a 25% (P < 0.05) reduction of the insulin stimulated incorporation of glucose into lipids. Concurrently, the basal conversion of (U-14C)D-glucose into 14CO2 increased (110%) in the leptin cultivated adipocytes and reached values (1.54 nmol/10(5) cells) similar to the insulin stimulated group (not cultivated with leptin) (1.40 nmol/10(5) cells). In addition, in the presence of insulin, the leptin cultivated adipocytes elicited a 162% (P < 0.05) increase in 14CO2 production that was significantly higher than the increase observed for the not-leptin-cultivated insulin group (92%). We conclude that leptin: 1) directly inhibits the insulin stimulated glucose incorporation into lipids; 2) stimulates glucose decarboxylation, and also potentiates the effect of insulin on glucose decarboxylation in isolated adipocytes. Leptin per se does not alter glucose incorporation into lipids. 相似文献
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