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排序方式: 共有1394条查询结果,搜索用时 62 毫秒
61.
MD Bachi EE Korshin P Ploypradith JN Cumming S Xie TA Shapiro GH Posner 《Canadian Metallurgical Quarterly》1998,8(8):903-908
A series of 4,8-dimethyl-4-phenylsulfonylmethyl-2,3-dioxabicyclo[3.3.1]+ ++nonanes, carrying a variety of substituents at position-8 (4) were prepared by a short and efficient method from R-(+)-limonene. Key reactions include thiol oxygen cooxidation, and alkylation and acylation of a sterically hindered tertiary alcohol compatible with the endoperoxy functionality. Some of compounds 4, which are structurally related to yingzhaosu A (2), were found to exhibit in vitro antimalarial activity comparable to that of artemisinin (1) and superior to that of arteflene (3). 相似文献
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G Velikova RE Banks A Gearing I Hemingway MA Forbes SR Preston NR Hall M Jones J Wyatt K Miller U Ward J Al-Maskatti SM Singh PJ Finan NS Ambrose JN Primrose PJ Selby 《Canadian Metallurgical Quarterly》1998,77(11):1857-1863
The concentrations of the soluble adhesion molecules E-cadherin, E-selectin, intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) were investigated in 48 patients with colorectal cancer before treatment, and their relation to clinical, histological and routine laboratory parameters was examined. Data were collected on tumour stage at presentation, presence and sites of metastatic disease, tumour pathology and results of routine laboratory tests. Serum concentrations of ICAM-1 and VCAM-1 were significantly elevated in the patients with colorectal cancer in comparison with a group of healthy subjects (P < 0.00001). Levels of circulating ICAM-1 and VCAM-1 were increased both in patients with local and those with metastatic disease. Although elevated in some patients soluble E-cadherin and E-selectin concentrations were not significantly elevated compared with the control group (P = 0.71 and P = 0.052 respectively). The levels of circulating ICAM-1 were significantly correlated with those of VCAM-1 and E-selectin. A correlation was also found between the serum concentrations of E-selectin and ICAM-1 and alkaline phosphatase, total white cell count and platelet count. VCAM-1 was positively correlated with age and negatively with degree of tumour differentiation and haemoglobin concentration. The biological implications and possible clinical relevance of these findings are discussed. 相似文献
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BACKGROUND AND OBJECTIVE: Experience with recombinant human erythropoietin (rHuEPO) in the treatment of the anemia secondary to myelofibrosis with myeloid metaplasia (MMM) is slight up to now. We present our results of the treatment of 6 patients and a review of the literature in search of possible parameters predicting response to this treatment. DESIGN AND METHODS: From January 1994 to June 1996 all transfusion-dependent patients with MMM diagnosed in our hospital were included in this study. We established a minimum period of 4 weeks of treatment and a maximum of 12 if no response was observed. Initial dosages used were 100 U/kg s.c. 3 times weekly, increasing by 50 U/kg every 4 weeks where no response was observed. Response was defined as a reduction > or = 30% of the previous transfusional needs. The review of the literature was made using a MEDLINE search (January 1990-December 1996) on the keywords erythropoietin, myelofibrosis, and agnogenic myeloid metaplasia. A statistical study was made in search of possible parameters to predict response. The parameters studied include age, sex, hemoglobin, serum erythropoietin (sEPO) levels, transfusional dependency, transfusional requirements per month prior to treatment, maximum dosages used and dosage at which response was obtained. RESULTS: Only 2 of our 6 patients responded, both at a dosage of 600 U/kg/week (200 U/kg 3 times weekly s.c.). In addition to our 6 patients we have found only 28 other patients in the literature. For statistical calculation 2 of our patients were not considered as they did not complete the period of study. The overall rate of response was 17/32 (53.1%). In the univariate analysis comparing responders and non-responders we found a tendency to significance with respect to sex (p = 0.07), sEPO (p = 0.07) and transfusional needs in units of packed red blood cells per month (PRBC/m) (p = 0.13). In this way patients with low sEPO, females and those with low transfusional needs (< 3 PRBC/m) respond better. This better response in females could be explained by the fact that their disease situation was more stable (with both lower sEPO levels and transfusional dependency). The best cut-off point in the sEPO to predict response was 123 mU/mL. No important side-effects have been observed except three cases of aggravation of splenomegaly. In two cases this condition improved when the rHuEPO was discontinued. The association of rHuEPO with hydroxyurea or interferon does not seem to affect the response. INTERPRETATION AND CONCLUSIONS: Though the number of patients is low, our data suggest that some MMM patients, in particular females and individuals with low sEPO levels and with low transfusional needs, might benefit from rHuEPO in terms of elevation of hemoglobin levels. Unfortunately, transfusion dependent-patients, i.e. those in whom a beneficial effect of rHuEPO would be most welcome, are unlikely to respond, and more generally, treatment is not cost effective in medically responsive patients. 相似文献
64.
A considerable portion of the W chromosome in Gallinaceous birds consists of tandem repetitive DNA. In the turkey, a 0.4-kb PstI element is repeated about 10,000 times in the female diploid genome but is undetectable as such a unit in males. In this study a multiplex polymerase chain reaction was developed to identify the sex of turkeys based upon the PstI repeat. The technique utilized two pairs of primers, the first pair was designed to amplify a region of the PstI repetitive element, resulting in the production of a 177-bp fragment in females. The other pair was designed to amplify a region of the adenosine triphosphate (ATP) synthase gene, present in both males and females. The simultaneous use of all four primers in the same reaction resulted in the coamplification of a 177-bp and a 250-bp fragment in females and a 250-bp fragment in males. This technique was used to verify the sex of 45 adults of known sex and to identify the sex of 74 embryos from Day 5 to hatch. This procedure is rapid and permits the sexing of many embryos in a short time. The ability to sex early embryos can facilitate studies on avian sex determination. 相似文献
65.
Pulmonary superoxide dismutase (SOD) plays an important role in the lung defense against O2 toxicity. We have previously demonstrated that tracheal insufflation of interleukin-1 alpha (IL-1) selectively enhances pulmonary MnSOD and protects rats against O2 toxicity. However, little is known about the cellular distribution of pulmonary MnSOD- and CuZnSOD-specific proteins. We performed immunohistochemistry in plastic sections (2 microns thick) to determine the effects of hyperoxia and IL-1 on the cellular distribution of pulmonary MnSOD and CuZnSOD in rats. MnSOD and CuZnSOD were present in all lung cells. Smooth muscle and endothelial cells appeared to contain higher immunoreactive MnSOD and CuZnSOD proteins than other lung cell types. Exposure of rats to 100% O2 for 24 hr had no effect on the cellular distribution and intensity of pulmonary MnSOD. However, at 50 hr after O2 exposure the intensity of pulmonary MnSOD was reduced. In contrast, tracheal insufflation of IL-1 markedly enhanced the intensity of pulmonary MnSOD in rats exposed to O2 for 50 hr. Neither O2 exposure nor IL-1 insufflation had any apparent effect on the distribution and intensity of pulmonary CuZnSOD. We conclude that IL-1 selectively enhances pulmonary MnSOD and that this effect is manifested in most lung cells, particularly smooth muscle and endothelial cells. 相似文献
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The art and science of speech recognition have been advanced to the state where it is now possible to communicate reliably with a computer by speaking to it in a disciplined manner using a vocabulary of moderate size. It is the purpose of this paper to outline two aspects of speech-recognition research. First, we discuss word recognition as a classical pattern-recognition problem and show how some fundamental concepts of signal processing, information theory, and computer science can be combined to give us the capability of robust recognition of isolated words and simple connected word sequences. We then describe methods whereby these principles, augmented by modern theories of formal language and semantic analysis, can be used to study some of the more general problems in speech recognition. It is anticipated that these methods will ultimately lead to accurate mechanical recognition of fluent speech under certain controlled conditions. 相似文献
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