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1.
The functional state of the amacrine cells which contain enkephalin-, neurotensin- and somatostatin-like immunoreactivity of the chicken retina was monitored by measuring the rate of change in the levels of [Leu]enkephalin-like immunoreactivity in the retina. Dark-adapted birds were exposed to lights of different intensities for 12 h. At light levels of < or = 0.03 microW/cm2, the ENSLI amacrine cells were highly active but, by 0.08 microW/cm2, they reached a state of maximum inactivation. Thus, the ENSLI amacrine cells act as flip-flop devices, inactivated by critical levels of light, which correspond to those which inactivate pineal melatonin synthesis. They may, therefore, be involved in retinal pathways which signal the difference between day and night.  相似文献   

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The purpose of this study was to evaluate the feasibility of a shorter method of performing platelet kinetic studies with respect to the conventional 8-9-day approach. METHODS: We studied 41 patients (28 women, 13 men; mean age 52 yr) with primary idiopathic thombocytopenic purpura (ITP) (n = 20), secondary ITP (n = 9), HCV associated thrombocytopenia (n = 9), splenectomy (n = 1) and hairy-cell leukemia (n = 1). The patients were in a steady-state of platelet turnover. Initial platelet counts ranged from 19 to 302 x 10(9)/liter (mean value = 83). Platelet survival times (PST) were measured from the blood radioactivity disappearance curve of 111In-oxine-labeled autologus platelets following the recommendations of the International Committee for Standardization in Haematology: blood samples were taken at 30 min and 2 and 4 hr and thereafter daily for 7 days. PST was calculated by the weighted mean method and ranged from 18 to 219 hr (mean value = 98). PST was also calculated using only the data collected at 2, 48 and 96 hr. If the radioactivity in the blood at 96 hr exceeded 10% of the 2-hr value, the additional point at 168 hr was used. RESULTS: By using this reduced dataset, we obtained a correlation of r = 0.97 with the PST obtained from the whole dataset. In 24 patients, the difference was between +/- 10 hr and exceeded 1 day in only 4. CONCLUSION: About 94% of the data may be recovered with only three or four blood samples and the duration may be shortened to 4 days in a significant proportion of patients (48% of ITP patients). This approach offers the advantages of increased patient throughput, compliance and reduced examination costs.  相似文献   

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We have characterized a new selenium-dependent glutathione peroxidase, GSHPx-GI, by expressing a GSHPx-GI cDNA isolated from human hepatoma HepG2 cells in human mammary carcinoma MCF-7 cells, which have virtually undetectable expression of either the classical cellular enzyme, GSHPx-1, or GSHPx-GI at the protein level. One of the G418-resistant clones, neo-D1, expresses the transfected GSHPx-GI cDNA. This is based on 1) the presence of an additional GSHPx-GI DNA restriction fragment detected by Southern analysis; 2) the presence of a 1.9-kilobase (kb) GSHPx-GI mRNA in addition to the 1.0-kb endogenous mRNA by Northern analysis; and 3) the appearance of a 22-kDa 75Se-labeled protein which is absent in parental MCF-7 cells revealed by SDS-polyacrylamide gel electrophoresis. GSHPx-GI expressed in neo-D1 is a tetrameric protein localized in cytosol. GSHPx-GI does not cross-react with antisera against human GSHPx-1 or human plasma glutathione peroxidase (GSHPx-P). Similar substrate specificities are found for GSHPx-1 and GSHPx-GI; they both catalyze the reduction of H2O2, tert-butyl hydroperoxide, cumene hydroperoxide, and linoleic acid hydroperoxide with glutathione, but not of phosphatidylcholine hydroperoxide. GSHPx-GI mRNA was readily detected in human liver and colon, and occasionally in human breast samples, but not other human tissues including kidney, heart, lung, placenta, or uterus. In rodent tissues, GSHPx-GI mRNA is only detected in the gastrointestinal tract, and not in other tissues including liver. In fact, GSHPx-GI appears to be the major glutathione-dependent peroxidase activity in rodent GI tract. This finding suggests that GSHPx-GI could play a major role in protecting mammals from the toxicity of ingested lipid hydroperoxides. In conclusion, we have demonstrated that GSHPx-GI is the fourth member in the selenium-dependent glutathione peroxidase family, in addition to GSHPx-1, GSHPx-P, and phospholipid hydroperoxide glutathione peroxidase (PHGPX).  相似文献   

5.
Monitoring the depth of sedation in patients under intensive care is difficult. Clinical assessment by the different scoring systems produces insufficient information, especially once deeply sedated patients become unresponsive to any external stimulation. Recently, the bispectral index (BIS), the result of computerized bispectral electroencephalographic monitoring, was found to be the best predictor of depth of anaesthesia during surgical intervention. This report concerns BIS monitoring in 18 randomly selected, deeply sedated, surgical patients in the intensive care unit, who were unresponsive to standard clinical stimulation (Ramsay sedation score). A wide range of BIS was observed, with 15 of the patients having a BIS below 60, indicating a state of deep sedation (or possibly over-sedation). Therefore, further studies using BIS monitoring in patients under intensive care are needed to determine if this method can guide sedation and prevent oversedation in this context and, most importantly, to analyse its final cost-benefit ratio.  相似文献   

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PURPOSE: To evaluate the effectiveness and safety of olopatadine hydrochloride and to determine its optimal concentration and the onset and duration of action for treating allergic conjunctivitis. Olopatadine is a new topical ophthalmic antiallergic agent that demonstrates activity as both an antihistamine and a mast cell stabilizer. Two double-masked, randomized, placebo-controlled, contralateral eye comparison studies were conducted using the conjunctival allergen challenge model. METHODS: A total of 169 subjects received 0.05% or 0.1% olopatadine. Study subjects were healthy adult men and women with a history of active allergic conjunctivitis within the previous two seasons but not receiving current treatment. With an allergen dose that produced signs and symptoms of allergic conjunctivitis at visits 1 and 2, the conjunctival allergen challenge was performed 27 minutes after study drug administration at the third visit (onset-of-action challenge) and at 8 hours after study drug administration at the fourth visit (duration-of-action challenge). Olopatadine was administered in one eye and placebo in the opposite eye. Itching and redness were scored for both eyes at 3, 10, and 20 minutes after the conjunctival allergen challenge. RESULTS: Both 0.05% and 0.1% concentrations of olopatadine were significantly (P < .05) more effective than placebo in inhibiting itching and redness at all evaluations when administered 27 minutes or 8 hours before the conjunctival allergen challenge. There were no serious or drug-related ocular or nonocular adverse events in either study. CONCLUSION: These findings demonstrate the rapid and prolonged (at least 8 hours) ocular antiallergic action of olopatadine.  相似文献   

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To evaluate the feasibility of nipple aspiration and to identify intermediate markers of breast cancer risk, nipple aspirate fluid (NAF) was collected from 177 subjects using a modified breast pump. The first 33 subjects demonstrated that we could obtain NAF quickly, reliably and repeatedly. Specimens from the remaining 144 subjects were collected to evaluate promising cellular biomarkers. NAF was obtained in 167 out of 177 (94%) subjects overall and in 99% of the 144 most recent subjects. Sufficient NAF was obtained to evaluate cytology in 160 out of 167 (96%) cases and specimens were sufficiently cellular to analyse DNA markers in 53% of cases. Among the last 144 subjects, menopausal status did not influence the ability to obtain NAF. NAF cytology correlated with increased breast cancer risk (P = 0.002). Using computerized image analysis of NAF epithelial cells, DNA index (P = 0.0002), percentage of cells in G2M (P = 0.05) and percentage of cells with hypertetraploidy (P = 0.002) increased as cytology became more abnormal. Our data indicate that NAF can be obtained in essentially all eligible subjects; that breast epithelial cells are evaluable in > 95% of NAF samples for cytology and in over half of NAF samples for DNA index (ploidy) and cell cycle analysis; and that abnormal NAF cytology correlates with increased breast cancer risk. This suggests that biomarkers identified in nipple aspirate fluid may prove useful either as an adjunct to currently accepted breast cancer screening methods, or to evaluate response to a chemopreventive agent.  相似文献   

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本文提出一种测定粉末粒度的新概念,采用颗粒各平表面到其中心按表面积加权平均距离的两倍来描述粉末颗粒大小,和传统的方法相比较,具有不需假设粉末颗粒为某种规则形状的前提条件,从而可较为准确的描述和表征形状复杂的颗粒尺寸,并且具有检测方便的特点。  相似文献   

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Carbamazepine (CBZ) concentrations were determined in the sections of head hair from 40 patients (22 males and 18 females), ages 5 to 81, who were receiving this drug systemically. Hair treatment included dissolution, liquid phase extraction procedures, and immunoassay (Abbott TDx) or high-pressure liquid chromatography (HPLC) analytical techniques. The mean values of CBZ levels in the hair from the 1st section (close to hair root) to the 5th section for female patients were 26.82, 19.18, 17.28, 15.09, and 14.62 micrograms/g according to HPLC measurements. Immunoassay gave generally slightly higher results. The mean values of CBZ in the hair sections according to the immunoassay technique were 30.53, 21.90, 19.83, 17.45, and 16.99 micrograms/g, respectively, from the 1st to the 5th sections. The corresponding mean values for male patients by HPLC and immunoassay techniques were 21.97, 17.30, 15.03, 13.02, and 11.21 micrograms/g and 25.98, 20.52, 17.15, 14.87, and 12.31 micrograms/g. Generally, a reduction of drug concentrations in hair from the first to the subsequent segments was observed. Higher amounts of CBZ were deposited in black, untreated hair (e.g., not dyed or permed). CBZ concentrations in hair sections were found to be dependent on the dosage (r = 0.979, p < or = 0.001) but not on the gender. The data indicate the possible use of hair section testing as a marker of the dosage history and the compliance of patients under long-term treatment with CBZ.  相似文献   

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8-hydroxy-2'-deoxyguanosine (8-OH-dG) was first reported in 1984 as a major form of oxidative DNA damage product by heated sugar, Fenton-type reagents and X-irradiation in vitro. 8-OH-dG has been detected in cellular DNA using an HPLC-ECD method in many laboratories. Analyses of 8-OH-dG in animal organ DNA after the administration of oxygen radical-forming chemicals will be useful for assessments of their carcinogenic risk. Its analysis in human leucocyte DNA and in urine is a new approach to the assessment of an individual's cancer risk due to oxidative stress. The increase of the 8-OH-dG level in the cellular DNA, detected by HPLC-ECD method, was supported by its immunochemical detection and its enhanced repair activity. The validity of the general use of 8-OH-dG as a marker of cellular oxidative stress is discussed.  相似文献   

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In order to shorten anaesthesia induction and to avoid pain of the intramuscular injection, we evaluated the efficacy and safety of midazolam given by a jet-injector, utilized solely for mass inoculations until now. Premedication with midazolam with the jet-injector, indeed, proved to be effective, rapid and safe in children. The best results were found in two groups receiving 150-200 microgram/kg midazolam. Within 5 minutes, it was easy to cannulate a vein in children injected by the jet-injector, whereas the effect of intramuscular injection developed slowly, within 7 minutes. In the latter group, cannulation of the vein was more difficult than in the other groups. The separation from the parents and anaesthetic induction were greatly facilitated by midazolam given by the jet-injector. Amnesia was present not only for anaesthetic induction but also for the injection. Recovery was not more prolonged in those premedicated with midazolam with the jet-injector than with midazolam administered by other routes: oral, rectal or nasal. The children induced with the aid of jet-injector had no unpleasant recall based on interviews with the patients and parents.  相似文献   

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A new formulation has been developed to describe the fluid dynamics of a liquid draining through an orifice under the influence of gravity. The model relates experimental quantities of head and flow rate, with surface tension, viscosity, and density, facilitating the calculation of all three properties. Experiments performed with molten aluminum at temperatures from 937 to 1173 K indicate that surface tension (N/m) and density (kg/m3) are [0.871 − 0.155 × 10−3 (TT liq)] and [2390 − 0.15 (TT liq)], which is within 6.5 and 2.5 pct, respectively, of values reported in the literature. The viscosity has been determined to be 5.2 × 10−4 Nsm−2, which is significantly less than data reported from other sources. The method is unique because the measurements are performed under highly dynamic conditions.  相似文献   

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Dramatic physiologic changes are part of normal human pregnancy. The physiologic alterations of pregnancy have the potential to affect chronic diseases, to unmask subclinical conditions, or to alter the presentation and course of newly acquired illnesses. An update in selected topics of obstetric medicine follows, focusing on clinical entities in which there have been significant advances in diagnosis or management. Additionally, reviews of selected medical disorders, such as HIV infection and asthma, that are rising in incidence in women of reproductive age are included.  相似文献   

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Recent high-resolution analysis of tubulin's structure has led to the prediction that the taxol binding site and a tubulin acetylation site are on the interior of microtubules, suggesting that diffusion inside microtubules is potentially a biologically and clinically important process. To assess the rates of transport inside microtubules, predictions of diffusion time scales and concentration profiles were made using a model for diffusion with parameters estimated from experiments reported in the literature. Three specific cases were considered: 1) diffusion of alpha beta-tubulin dimer, 2) diffusion/binding of taxol, and 3) diffusion/binding of an antibody specific for an epitope on the microtubule's interior surface. In the first case tubulin is predicted to require only approximately 1 min to reach half the equilibrium concentration in the center of a 40 microns microtubule open at both ends. This relatively rapid transport occurs because of a lack of appreciable affinity between tubulin and the microtubule inner surface and occurs in spite of a three-fold reduction in diffusivity due to hindrance. By contrast the transport of taxol is much slower, requiring days (at nM concentrations) to reach half the equilibrium concentration in the center of a 40 microns microtubule having both ends open. This slow transport is the result of fast, reversible taxol binding to the microtubule's interior surface and the large capacity for taxol (approximately 12 mM based on interior volume of the microtubule). An antibody directed toward an epitope in the microtubule's interior is predicted to require years to approach equilibrium. These results are difficult to reconcile with previous experimental results where substantial taxol and antibody binding is achieved in minutes, suggesting that these binding sites are on the microtubule exterior. The slow transport rates also suggest that microtubules might be able to serve as vehicles for controlled-release of drugs.  相似文献   

17.
A radioassay employing (3H) thymidine, to measure inhibition of growth of Staphylococcus aures by human phagocytes is presented. The principle of this new method is that viable and dividing staphylococci take up thymidine more rapidly than white cells, so that whereas in control cultures containing staphylococci alone high counts per minute (cpm) are obtained within 90 min of incubation in test cultures both leucocytes and plasma from 25 normal subjects reduced the cpm, following ingestion and killing of staphylococci.  相似文献   

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Intraoperative choline acetyltransferase activity measurements were used to evaluate the functional status of donor nerves during reinnervated free muscle transfer. This technique was applied to 3 cases. One was a lower-type brachial plexus injury in combination with radial nerve injury; the other 2 were Volkmann's ischemic contractures. Gracilis muscle was transferred for reconstruction of wrist extension in all cases. The donor nerves included 1 anterior interosseous nerve and 2 posterior interosseous nerves. A fascicle with choline acetyltransferase activity above 2,000 cpm was considered to be reliable as a motor fascicle. Reinnervation of transferred muscle was confirmed by electromyographic examination within the first 3.3 months (range, 2.5 to 4 months) after surgery and all muscles obtained useful recovery. This technique can directly and quantitatively verify the functional quality of the donor motor fascicle when the quality of the donor nerve is in doubt.  相似文献   

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Three experiments investigated children's understanding of inference as a source of knowledge. Children observed a puppet make a statement about the color of one of two hidden toys after the puppet (a) looked directly at the toy (looking), (b) looked at the other toy (inference), or (c) looked at neither toy (guessing). Most 4-, 5-, and 6-year-olds did not rate the puppet as being more certain of the toy's color after the puppet looked directly at it or inferred its color than they did after the puppet guessed its color. Most 8- and 9-year-olds distinguished inference and looking from guessing. The tendency to explain the puppet's knowledge by referring to inference increased with age. Children who referred to inference in their explanations were more likely to judge deductive inference as more certain than guessing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)  相似文献   

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